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GEOLOGY OF THE SANDYMUSH AND CANTON 
QUADRANGLES, NORTH CAROLINA 

N.C. DOCUMENTS 



CLEA 



r: :.r>iir\ 



USE 



MAR 13 1989 



by 



N.C. SirtiL LIBRARY 
RALflGH 
Carl E. Merschat and Leonard S. Wiener 



BULLETIN 90 




NORTH CAROLINA GEOLOGICAL SURVEY 

DIVISION OF LAND RESOURCES 

DEPARTMENT OF NATURAL RESOURCES 
AND COMMUNITY DEVELOPMENT 

RALEIGH, 1988 




Cover: Distinctly layered, heterogeneous, folded, and highly jointed gneisses and schists character- 
istic of the Earlies Gap Biotite Gneiss. Exposure is at the formation's type locality near Payne 
Chapel along Secondary Road 1394 west of its intersection with Secondary Road 1401, 
Sandymush Quadrangle, North Carolina. 



GEOLOGICAL SURVEY SECTION 

The Geological Survey Section shall by law "...make such examination, survey, and mapping 
of the geology, mineralogy, and topography of the state, including their industrial and economic 
utilization as it may consider necessary." 

In carrying out its duties under this law, the Section promotes the wise conservation and use 
of mineral resources by industry, commerce, agriculture, and governmental agencies for the general 
welfare of the citizens of North Carolina. 

The Section conducts a number of basic and applied research projects in environmental 
geology, mineral resource exploration, mineral statistics, and systematic geologic mapping. Serv- 
ices constitute a major portion of the Section's activities and include identifying rock and mineral 
samples submitted by the citizens of the state and providing consulting services and specially 
prepared reports to agencies that require geological information. 

The Geological Survey Section publishes results of research in a series of Bulletins, 
Economic Papers, Information Circulars, Educational Series, Geologic Maps, and Special Publica- 
tions. For a complete list of publications or more information about the Section please write: 
Geological Survey Section, P.O. Box 27687, Raleigh, North Carolina 2761 1 . The telephone number 
is: (919) 733-2423. 



Jeffrey C. Reid 
Chief Geologist 



GEOLOGY OF THE SANDYMUSH AND CANTON 
QUADRANGLES, NORTH CAROLINA 



by 

Carl E. Merschat and Leonard S. Wiener 

BULLETIN 90 



NORTH CAROLINA GEOLOGICAL SURVEY 

DIVISION OF LAND RESOURCES 
DEPARTMENT OF NATURAL RESOURCES AND COMMUNITY DEVELOPMENT 

RALEIGH, 1988 



CONTENTS 



Page 

Abstract 1 

Introduction 2 

Location and Access 2 

Physiographic Setting 2 

Previous Work 4 

Present Investigation 5 

Rock Descriptions 6 

Richard Russell Formation 7 

Field Occurrence and Description . 7 

Petrography 9 

Age, Contact Relationship, 

andProtolith 9 

Earlies Gap Biotite Gneiss 10 

Field Occurrence and 

Description 10 

Petrography 11 

Age, Contact Relationship, 

andProtolith 12 

Sandymush Felsic Gneiss 14 

Field Occurrence and Description . 14 

Petrography 14 

Age, Contact Relationship, 

andProtolith 15 

Spring Creek Granitoid Gneiss 15 

Field Occurrence and Description . 15 

Petrography 18 

Age, Contact Relationship, 

andProtolith 18 

Doggett Gap Protomylonitic Granitoid 

Gneiss 20 

Field Occurrence and Description . 20 

Petrography 20 

Age and Contact Relationship 20 

- Talc Body 22 

Field Occurrence and Description . 22 

Petrography 22 

Age, Contact Relationship, 

andProtolith 22 

Ashe Metamorphic Suite 22 

Schist 23 



Page 

Field Occurrence and 

Description 23 

Petrography 23 

Gneiss 24 

Field Occurrence and 

Description 24 

Petrography 27 

Age and Contact Relationship 27 

Dunite 28 

Field Occurrence and Description . 28 

Petrography 28 

Age and Contact Relationship 29 

Altered Mafic and Ultramafic Rock ... 29 

Field Occurrence and Description . 29 

Petrography 29 

Age, Contact Relationship, 

andProtolith 29 

Snowbird Group 30 

Field Occurrence and Description . 30 

Petrography 30 

Age and Contact Relationship 30 

Mylonite and Protomylonite 32 

Field Occurrence and Description . 32 

Petrography 32 

Age and Contact Relationship 32 

Trondhjemite 33 

Field Occurrence and Description . 33 

Petrography 33 

Age and Contact Relationship 33 

Pegmatite 33 

Field Occurrence and Description . 33 

Petrography 33 

Age and Contact Relationship 34 

Surficial Deposits 34 

Alluvium 34 

Colluvium 34 

Age 35 

Geologic Structure 35 

Proterozoic Structures 35 

Early Paleozoic Structures 37 



CONTENTS (continued) 



Page 

Later Paleozoic Deformation 39 

Mesozoic and Cenozoic Structures 41 

Metamorphism 44 

Proterozoic Metamorphism 44 

Early Paleozoic Metamorphism 46 

Retrogression 48 

Timing 48 

Late Paleozoic Metamorphism 49 

Mineral Resources 49 

Acknowledgements 49 

References Cited 50 



Page 

Appendices 56 

Appendix 1 . Heavy Mineral 

Procedure 56 

Appendix 2. Heavy Mineral 

Analyses of Panned Concentrates, 

Canton and Sandymush 

Quadrangles 56 

Appendix 3. Summary of Mines, 

Pits, Prospects, and 

Occurrences 62 



ILLUSTRATIONS 

Page 

Plate 1. Geologic map of the Sandymush Quadrangle, North Carolina In pocket 

2. Geologic map of the Canton Quadrangle, North Carolina In pocket 

Figure 1. Location map for the Sandymush and Canton Quadrangles 3 

2. Physiographic subdivisions of the Sandymush and Canton 

Quadrangles 4 

3. North Carolina Secondary Roads 8 

4-13. Photographs of: 

4. Richard Russell Formation 9 

5. Earlies Gap Biotite Gneiss 1 1 

6. Earlies Gap Biotite Gneiss, photomicrographs 13 

7. Sandymush Felsic Gneiss 16 

8. Spring Creek Granitoid Gneiss 19 

9. Doggett Gap Protomylonitic Granitoid Gneiss 21 

10. Schist unit of the Ashe Metamorphic Suite, photomicrographs 25 

11. Ashe Metamorphic Suite, Schist unit 26 

12. Ashe Metamorphic Suite, Gneiss unit 26 

13. Snowbird Group 31 

14. Map showing foliation trends 38 

15. Mylonitization 40 

16. Contoured stereoplots of joint orientations 42 

17. Orientation of joint maxima shown by strike and dip symbols 43 

18. Graphs showing average abundance of heavy minerals 45 

19. Outline map showing location of the sillimanite-kyanite isograd and 

distribution of monazite-bearing rocks , 47 

TABLES 



Page 

Table 1. Names and type areas of newly defined formations 7 

2. Grain size and layer thickness terms 7 

3-10. Modal analyses of: 

3. Richard Russell Formation 10 

4. Earlies Gap Biotite Gneiss 13 

* 5. Sandymush Felsic Gneiss 17 

6. Spring Creek Granitoid Gneiss 19 

7. Doggett Gap Protomylonitic Granitoid Gneiss 21 

8. Schist unit of the Ashe Metamorphic Suite 25 

9. Gneiss unit of the Ashe Metamorphic Suite 27 

10. Snowbird Group 31 

11. Geologic development of the Sandymush and Canton area 36 



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GEOLOGY OF THE SANDYMUSH AND CANTON QUADRANGLES, 

NORTH CAROLINA 



Bulletin 90 



By Carl E. Merschat and Leonard S. Wiener 



ABSTRACT 

The bedrock geology of 122 square miles in the 
central Blue Ridge of North Carolina is the subject of this 
report. The rocks are mostly multi-deformed, amphibolite - 
facies gneisses and schists of Proterozoic age. 

A Middle Proterozoic basement sequence underlies 
approximately 60 percent of the area and is divided into five 
map units. One is correlated with the Richard Russell 
Formation; four other units are here defined and formally 
named. They are the Earlies Gap Biotite Gneiss, the Sandy- 
mush Felsic Gneiss, the Spring Creek Granitoid Gneiss, and 
the Doggett Gap Protomylonitic Granitoid Gneiss. The 
Richard Russell Formation is dominated by discontinuous, 
well-foliated biotite gneiss layers. The biotite gneiss is 
commonly migmatitic and at places grades to metagray- 
wacke. Interlayers of amphibolite are also present. The 
Earlies Gap Biotite Gneiss mostly contains well layered 
biotite gneiss with abundant interlayers of amphibolite and 
minor interlayers of calc-silicate granofels. Most felsic 
layers have granodioritic compositions. The formation is 
characterized by its wavy foliation and the common presence 
of thin layers of coarse-grained biotite flakes in the foliation 
planes. The Sandymush Felsic Gneiss is a very thick, hetero- 
geneous sequence of layered rocks. Biotite granitic gneiss to 
quartz dioritic gneiss dominates. Interlayers of biotite schist, 
biotite gneiss, and amphibolite are common throughout the 
unit. Parts of the Sandymush Felsic Gneiss and the Earlies 
Gap Biotite Gneiss resemble each other very closely. The 
two units have a gradational boundary with each other and are 
essentially the same age. They may represent a related 
plutonic-volcanic accumulation with the protolith of the 
Sandymush Felsic Gneiss having originated as the more plu- 
tonic phase and the Earlies Gap representing the volcanic- 
dominated phase. 

The Spring Creek Granitoid Gneiss is mostly a poorly 
foliated to foliated, coarse-grained biotite granitic gneiss. 
Mylonitic textures occur throughout the formation with 



approximately 1 5 percent of the unit consisting of mylonitic 
and protomylonitic interlayers. The Doggett Gap Protomy- 
lonitic Granitoid Gneiss is largely a distinctive, very coarse- 
grained gneissic granitic rock that has been extensively 
mylonitized. The Spring Creek and Doggett Gap protoliths 
were granitic bodies, here interpreted as having intruded the 
older Sandymush Felsic Gneiss. 

Cover rocks, assigned to the Late Proterozoic, are 
locally represented by parts of the Ashe Metamorphic Suite 
and the Snowbird Group. The Ashe formed from a mixed 
assemblage of clastic sediments and minor volcanics. It is di- 
vided into two main subunits, one dominated by aluminous 
schist and the other dominated by metagraywacke to mica 
gneiss. Snowbird rocks are largely kyanite-garnet mica 
schist of pelitic origin interbedded with lesser metagray- 
wacke and minor calc-silicate granofels. The Ashe overlies 
the basement rocks along a major thrust fault; the Snowbird 
nonconformably overlies the Spring Creek Granitoid Gneiss. 

Small intrusive bodies are also present in the area. 
Included here are pegmatite, trondhjemite, dunite, and other 
altered mafic and ultramafic bodies. 

Minor surficial deposits of alluvium occur in the 
flood plains and stream channels. Colluvial material, rang- 
ing from clay particles to huge boulders, covers much of the 
sloping land in the area. 

A major, complex, deformational and metamorphic 
episode, correlated with the Middle Proterozoic Grenville 
orogeny, affected the older rocks in the area. Although later 
events have largely obliterated Grenville-age features, evi- 
dence for Proterozoic folding, amphibolite-grade metamor- 
phism, intrusion of plutons, and regional mylonitization still 
remains. Paleozoic events, associated with the Taconic 
orogeny, include transposition of earlier features into the 
planes of a new pervasive regional foliation. Subsequently. 
a major tectonic feature, here named the Holland Mountain 
thrust fault, developed and die rocks with their contained 



structures were then folded. Prograde Barrovian metamor- 
phic effects are well displayed in pelitic units where porphy- 
roblasts of staurolite.kyanite, or sillimanite are common. The 
kyanite-sillimanite isograd is closely located with its trace 
generally oblique to the regional structures. Therefore, much 
of the structural deformation must have preceded or, at the 
latest, been contemporaneous with the metamorphic peak. 
This Paleozoic metamorphic episode also had a retrogressive 
effect on some older, Middle Protcrozoic rocks. Most nota- 
bly, thin amphibolitc layers were converted to biotite schist. 

A mylonitic to protomylonitic fabric, likely devel- 
oped in late Paleozoic time, is widely present. It occurs both 
as an overprint at various isolated outcrops and as more or less 
continuous zones up to a quarter mile wide and several miles 

long. 

The orientations of several hundred joints were meas- 
ured. The majority have a northwest-southeast trend and a 
lesser group has an cast- west trend. 

Mining has not been a major industry in the area. 
Mica, feldspar, sand and gravel, and stone were of greatest 
commercial value. Other commodities mined or prospected 
on a small scale include kaolin, soapstone, corundum (in- 
cluding sapphire), and olivine. During this study scheelite 
and monazite were discovered in many stream sediment 
samples. The scheelite is restricted to streams draining the 
Middle Protcrozoic, amphibolite-bearing Earlies Gap and 
Sandymush Felsic Gneiss units. Monazite formed in the 
area's pelitic rocks where the metamorphic grade was suffi- 
ciently high. 



INTRODUCTION 

This report presents the results of a detailed 
study of the bedrock geology of the Sandymush 
and Canton 7 1/2-minute Quadrangles, North Caro- 
lina. The mapping project was prompted by the 
U.S. Department of Energy's announcement in 
early 1986 that a 105-square-mile area centered on 
the two quadrangles was one of a dozen sites in the 
eastern United States proposed as potentially ac- 
ceptable for deep burial of high-level radioactive 
waste (U.S. Department of Energy, 1986). How- 
ever, for this specific area no comprehensive 
geologic report had ever been prepared and the few 
existing geologic maps were only of reconnais- 
sance nature. The present field-based investiga- 
tion has resulted in the first detailed geologic maps 



and rock descriptions for the Sandymush-Canton 
area. The basic, factual data accumulated during 
the study reveal that local geologic conditions do 
not meet the Department of Energy's stated criteria 
for acceptability as a high-level radioactive- waste 
repository. (See the supplernent to this report [Mer- 
schat and Wiener, 1988] for a discussion of the 
area's non-suitability as a repository.) 

Location and Access 

The study area covers parts of Buncombe, 
Haywood, and Madison Counties. It is bounded by 
latitudes 35°30' and 35°45' North, and longitudes 
82°45' and 82°52'30" West. Canton, located in the 
southern part of the area, is the largest community 
and is the area's only incorporated town. Its 
population is about 4,700. Asheville, the largest 
city in the nearby region, is approximately 15 miles 
to the east (figure 1). 

A major regional transportation corridor 
extends across the southern part of the two-quad- 
rangle area. Included here are Interstate Highway 
40, U.S. Routes 19, 23 and 74, and a line of the 
Norfolk Southern Railroad. State Highway 63 
crosses the area's northern part and other state- 
maintained paved and unpaved roads extend into 
many valleys. Farm, logging, and development 
roads provide access to some of the ridges and 
hillsides. Much of the steeper ground and higher 
terrain, however, is best accessible by foot. 

Physiographic Setting 

The Sandymush-Canton area is centrally 
located within the widest part of the Blue Ridge 
province of the Appalachian highlands (Fenne- 
man, 1938). In a major study encompassing the 
Blue Ridge, Hack (1982), divides the southern 
section of the province into several areas based on 
topographic similarities and differences. Portions 
of three of Hack's subdivisions are present in the 
Sandymush-Canton area. They are the Way- 
nesville-Canton basin, the Asheville basin, and the 
Southern Blue Ridge highlands (figure 2). 




Cantori\Quadrangle 



miles 



Figure 1. Location map for the Sandymush and Canton Quadrangles, North Carolina. 




The Canton-Waynesville basin is drained 
by the Pigeon River and its tributaries along with 
the upper reaches of Hominy Creek and several of 
its tributaries. The Pigeon River leaves the area at 
an elevation of about 2,540 feet; the low, rounded 
hills within the basin do not^exceed 2,900 feet. The 
basin itself, especially its north and west margins, 
is fairly well delimited by the 2,800- to 2,900-foot 
contour interval. The basin floor was developed at 
about this level, but it is now being dissected with 
only the peaks of low knobs and ridges still pre- 
serving the 2,800- to 2,900-foot level. 

Part of the Asheville basin extends finger- 
like into the Sandymush-Canton area. The basin is 
represented by valley areas along Sandymush Creek 
and some of its tributaries, especially North Turkey 
Creek, Sugar Creek, Willow Creek, and Little 
Sandymush Creek. The lowest elevation, about 
2,000 feet, occurs where Sandymush Creek leaves 
the area. The basin floor gradually rises upstream 
to about 2,300 to 2,400 feet at which elevation the 
mountain hillsides are encountered. Low hills and 
rounded ridges, particularly from the vicinity of 
Canto westward to the Robinson Cove and Long 
Branch area, rise to elevations of 2,400 to 2,500 
feet. (Canto is located along N.C. Highway 63 near 
the east edgeof the Sandymush Quadrangle.) They 
seemingly mark the remnants of an old lowland 
that is now being dissected and consumed by 
Sandymush Creek. 

The mountainous portion of the study area is 
included in Hack's (1982) Southern Blue Ridge 
highlands. Locally, the maximum elevation of 
4,850 feet is on Little Sandymush Bald near the 
area's west edge. A number of other peaks and 
connecting ridges exceed 4,000 feet. Mountain- 
side slopes of 40 to 50 percent are common through- 
out the area. Rock cliffs are present, but not 
dominant. The local relief is a thousand feet or 
more, typical of the Blue Ridge highlands. 



Figure 2. Physiographic subdivisions of the Sandymush 
and Canton Quadrangles after Hack (1982). Waynes- 
villc-Canton Basin (dotted), Asheville Basin (ruled), 
and Southern Blue Ridge Highlands. 



Previous Work 



Several earlier geologic maps include the 



Sandymush and Canton Quadrangles. Those of the 
19th century, notably Kerr's pioneer geologic map 
of North Carolina (1875), are now primarily of 
historical interest. About the turn of the century, 
the U.S. Geological Survey embarked on an ambi- 
tious, comprehensive topographic and geologic 
mapping effort in the Appalachian region. As part 
of this project, Arthur Keith mapped in the south- 
ern Appalachians in the early 1900 's. His geologic 
map in the Sandymush-Canton area is at the inter- 
mediate scale of 1:125,000 (Keith, 1904). Keith's 
perceptive map and accompanying text remained 
the primary data source for many succeeding 
compilations including the 1958 Geologic Map of 
North Carolina (Stuckey, 1958). 

In 1971, Hadley and Nelson published a new 
regional map at a scale of 1:250,000 (Hadley and 
Nelson, 1971). This map incorporated and set forth 
major changes in stratigraphic nomenclature and 
geologic interpretation. They compiled existing 
data and used much new information obtained 
from numerous road traverses and a few foot tra- 
verses. 

In 1985, a major revision of the North Caro- 
lina State Geologic Map, scale 1:500,000, was 
published (North Carolina Geological Survey, 
1985). Representation of the geology in the Sandy- 
mush-Canton area is based on the older maps, 
extrapolation of trends shown on all available 
published and unpublished work in nearby areas, 
and data from a few road traverses. 



Both Keith (1904) and Hadley and Nelson 
(1971) present cross sections that depict the geo- 
logic structure. However, these sections, espe- 
cially those of Hadley and Nelson, are extremely 
generalized. 

Several of the ultramafic bodies and corun- 
dum occurrences in the area are mentioned in Pratt 
and Lewis (1905), Hunter (1941), Penso (1981), 
and Hirt et al. (1987). Sketch maps of the large 
dunite body near Newfound Gap are in Hunter 
(1941, p. 66), Penso (1981), and Hirt et al. (1987). 

A few pegmatite bodies located in the S andy- 
mush and Canton Quadrangles have been pros- 
pected or exploited for muscovite mica or feldspar. 
The available statistics are tabulated by Lesure 
(1968, p. 90-93). Olson and Parker (1943) pre- 
pared a mine map of the Big Cove Mica Mine, the 
largest of these mines. 

Several studies present small-scale maps 
showing the distribution of metamorphic index 
minerals in the Blue Ridge (Carpenter, 1 970; Hadley 
and Nelson, 1971;North Carolina Geological Sur- 
vey, 1985). These all show sillimanite in the 
southeastern part of the two quadrangles. Kyanite 
or kyanite-staurolite is shown occupying a broad 
band that trends diagonally across the center of the 
area. The northwestern corner of the Sandymush 
Quadrangle contains the lowest metamorphic-grade 
rocks of the study area. 



The three regional maps (Keith, 1904; Hadley 
and Nelson, 1971; North Carolina Geological Sur- 
vey, 1985) have several stratigraphic elements in 
common. They all show a small area of metasedi- 
mentary rocks in the Little Sandymush Bald re- 
gion. They also depict an area of granitic rocks in 
the northwestern part of the Sandymush Quad- 
rangle. Aside from several small ultramafic bod- 
ies, the remainder of the two quadrangles is shown 
as underlain by a complex of gneisses and schists. 
These rocks have been interpreted and classified 
differently by the various authors. 



Present Investigation 

Geologic field work began in March, 1986 
and was essentially completed in June, 1987. Dur- 
ing the summer of 1986, stream sediment samples 
for a heavy mineral study were collected through- 
out the area. Much of December 1986, and January 
through March 1987 was spent doing laboratory 
work. During the summer and fall of 1987, addi- 
tional traverses were made to provide more infor- 
mation in selected areas, and the remaining labo- 
ratory work was completed. Preparation of the 
map and text continued into 1988. 



Standard field methods were used. The area 
was covered by a network of foot traverses, rock 
fabric orientations were measured with Brunton 
compasses, and field identification of rocks and 
minerals were based on hand-lens examination. 
Data were plotted directly on 7 1/2-minute field 
sheets, and pocket altimeters were useful aids in es- 
tablishing field locations. The stream sediment 
samples were panned in the field and the concen- 
trates were brought back for further concentration 
and study (see Appendix 1). 

This investigation has resulted in the first 
detailed geologic maps and rock descriptions for 
the Sandymush and Canton Quadrangles. The 
present detailed work confirms the general distri- 
bution pattern for major rock classes shown on 
earlier maps. However, accurate location of the 
major unit boundaries is now established and 
subunits or minor units have been identified, de- 
lineated, and described. In addition, observations 
and interpretation of the area's geologic structures, 
metamorphic history, and economic mineral de- 
posits are presented in this report. 



ROCK DESCRIPTIONS 

One result of past geologic investigations in 
the Blue Ridge has been the development of a 
stratigraphic framework for the area's rocks. It is 
now established that an old basement complex is 
overlain by younger groups of cover rocks. The 
cover rocks are largely metasediments; in contrast, 
the basement rocks appear to have a much greater 
plutonic and volcanic complement. At some places 
a profound unconformity separates the two, but at 
other places the boundary is a tectonic feature. 
Both sequences commonly contain monotonous 
and repetitive-looking rocks that do not contain 
fossils or other unique markers, thus severely 
hampering stratigraphic interpretations. In addi- 
tion, they have a complex structure and exhibit an 
overriding, variable, and even multiple metamor- 
phic imprint. Of the two, the distribution and 
internal stratigraphy of the cover rocks is better 
understood, at least in general terms. In the Sandy- 



mush and Canton Quadrangles, the cover is repre- 
sented by parts of the Late Proterozoic Ashe Meta- 
morphic Suite and the Snowbird Group. 

The basement complex remains more diffi- 
cult to decipher. These ropks are chiefly layered, 
biotite-bearing felsic gneisses and relatively mas- 
sive granitoid gneisses, along with a substantial 
component of more mafic rocks. They are older 
than the cover rocks with many having Middle 
Proterozoic ages between 1 .0 and 1.3 billion years. 
In this report, the more massive granitoid gneisses 
are interpreted as having intruded preexisting, 
layered gneisses. In the Sandymush and Canton 
Quadrangles five extensive basement rock units 
were distinguished during field work. One of these 
units is correlated with the Richard Russell Forma- 
tion of Georgia; for the others new formational 
names were needed. The formational names here 
introduced are: the Earlies Gap Biotite Gneiss, the 
Sandymush Felsic Gneiss, the Spring Creek Grani- 
toid Gneiss, and the Doggett Gap Protomylonitic 
Granitoid Gneiss (table 1). 

Small intrusive bodies are also present. These 
include pegmatite, trondhjemite, dunite, other al- 
tered mafic and ultramafic bodies, and four small 
talc bodies presumed to be derived from ultramafic 
intrusives. In addition, there are also surficial 
deposits of alluvium and colluvium. 

Rock descriptions, presented on the follow- 
ing pages, are based on routine observations in the 
field and petrographic examination of selected 
samples. Several standard terms are used through- 
out the descriptions to describe grain size and 
thickness of compositional layers. These terms 
and their quantitative limits are listed in table 2. 

Petrographic study and modal analysis was 
greatly aided by use of thin sections selectively 
stained for both K-feldspar and plagioclase. 
Through staining, misidentification of the large 
proportion of untwinned feldspar grains was 
avoided. Rock names follow the plutonic rock 
terminology of the I.U.G.S. classification system 
(Streckeisen, 1976). 



Table 1. Names and type areas of newly defined formations (refer to figure 3 for road locations) 





Source of Geographic 




Names Used on Previous 


Name 


Name 


Type Locality 


Reconnaissance Maps 


Doggett Gap Proto- 


Doggett Gap, at the 


Roadside outcrops along N.C. 


Max Patch Granite (Keith, 1904;; 


mylonitic Granitoid 


Buncombe County-Madison 


Highway 63, from 0.4 miles 


Max Patch Granite and Cranberry 


Gneiss 


County boundary, Sandymush 


west of Doggett Gap to 0.7 


Gneiss (Hadley and Nelson, 1971); 




Quadrangle 


miles east of Doggett Gap 


Biotite granitic gneiss (N.C. Geo- 
logical Survey, 1985) 


Spring Creek 


Spring Creek community, 


Roadside outcrops along N.C. 


Cranberry Granite (Keith, 1904); 


Granitoid Gneiss 


Madison County, Spring 


Highway 63, from 0.4 to 1.2 


Max Patch Granite and Cranberry 




Creek Quadrangle 


miles northwest of Doggett Gap 


Gneiss (Hadley and Nelson, 1971); 
Biotite granitic gneiss (N.C. Geo- 
logical Survey, 1985) 


Sandymush Felsic 


Sandymush community, 


Outcrops along N.C. Highway 63, 


Carolina Gneiss (Keith, 1904); 


Gneiss 


Buncombe County, Sandy- 


2,000 feet west of confluence 


Layered gneiss and migmatite 




mush Quadrangle 


of Sandymush Creek and Little 


(Hadley and Nelson, 1971); Biotite 






Sandymush Creek 


granitic gneiss (N.C. Geological 
Survey, 1985) 


Earlies Gap Biotite 


Earlies Gap, Buncombe 


Extensive roadside outcrop along 


Carolina Gneiss and Roan Gneiss 


Gneiss 


County, Sandymush 


SR 1394, approximately 300 feet 


(Keith, 1904); Layered gneiss and 




Quadrangle 


southwest of its junction with 


migmatite (Hadley and Nelson, 






SR 1401 


1971); Biotite granitic gneiss 
(N.C. Geological Survey, 1985) 



Richard Russell Formation 

FIELD OCCURRENCE AND DESCRIPTION 

The Richard Russell Formation was named 
by Gillon (1982) and formalized by Nelson and 
Gillon (1985) for usage in Georgia and North 
Carolina. Rocks correlated with the Richard Russell 
Formation crop out in the southwestern corner of 
the Canton Quadrangle. They underlie about five 
percent of the quadrangle and consist principally 
of biotite gneiss with lesser metagraywacke and 
amphibolite. Aluminous layers common to the 
Richard Russell in its type area in Georgia, about 
75 miles to the southwest, are not present. Migma- 
tization is locally present throughout. 

Biotite gneiss layers make up 85 percent of 
the Richard Russell Formation. The unweathered 
rock is very light gray to medium light gray. Dis- 
continuous layering is very prominent and varies 
from medium to thick. The biotite gneiss is com- 
monly migmatitic with neosome pods and stringers 
composed chiefly of quartz and feldspar. Locally, 
the rocks have a high enough quartz content to 
resemble metagraywacke (see figure 4). 



Table 2. Grain size and layer thickness terms used in rock 
descriptions (grain size after Williams et al., 1954; layer 
thickness adapted from Ingram, 1954) 



Grain Size 


Layer Thickness 


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Very Thick 


— 3 cm — 


— 1 meter — 


Coarse 


Thick 


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— 30 cm — 


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Medium 


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— 10 cm — 


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Figure 3. North Carolina Secondary Roads in parts of the Sandymush and Canton Quadrangles. A, Worlcy Cove section, 
Madison County. B, Earlies Gap-Payne Chapcl-Sandymush area, Buncombe County. C, Wilson Cove-West Cove 
area, Haywood County. D, Hominy Grove area, Haywood County. Underlined four-digit numbers arc Secondary Road 
numbers; decimal numbers show distance (in miles) between road intersections. 



8 



Amphibolite layers make up about 15 per- 
cent of the Richard Russell Formation on the Canton 
Quadrangle. They are interlayered with biotite 
gneiss and metagray wacke and have variable thick- 
nesses ranging up to about ten meters. The amphi- 
bolite layers are commonly discontinuous to 
podiform in shape and are dark greenish gray to 
greenish black. 



PETROGRAPHY 

The biotite gneiss layers are well foliated at 
a scale from a millimeter to centimeters. The felsic 
portion of the gneiss has a granitic composition. 
The modal composition is shown in table 3. The 
garnet content is particularly variable and as esti- 
mated in the field, may be as much as 20 percent 
locally. 

The amphibolite is well foliated and exhib- 
its a nematoblastic texture. Mineralogically it is 
similar to amphibolites and hornblende-biotite 
gneisses in the Carolina Gneiss in the Dellwood 
Quadrangle (Hadley and Goldsmith, 1963). 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

Radiometric age data are not available for 
the Richard Russell Formation in the Canton Quad- 
rangle or indeed anywhere else. Nelson and Gillon 
( 1 985) class the Richard Russell as Late Proterozoic. 
Most previous workers have called these rocks 
Precambrian or Late Precambrian. The Geologic 
Map of North Carolina (North Carolina Geological 
Survey, 1985) classifies rocks along strike from the 
type Richard Russell as Late to Middle Proterozoic. 
However, in the study area a possible connection of 
the' Richard Russell with the Earlies Gap beneath 
the Holland Mountain thrust sheet favors the Middle 
Proterozoic age assignment. 

In the Canton Quadrangle, the Richard 
Russell Formation has a minimum thickness of 
2,000 feet. It is everywhere in fault contact with 




Figure 4. Richard Russell Formation. Above, Light-col- 
ored migmatitic biotite gneiss with prominent medium 
to thick layering. Outcrop is 3 miles southwest of 
Canton along N.C. Highway 2 15. Below, Photomicro- 
graph of typical biotite gneiss showing granoblastic 
texture in felsic layers dominated by quartz (Qtz), pla- 
gioclase (PI), and microcline (Mcr). Schistosity is 
marked by lepidoblastic biotite (Bt). Crossed polariz- 
ers, sample 2193. 



Table 3. Modal analyses (in percent) of Richard Russell Formation 

Sample No. N.C. Coordinates 

1768 663.350N; 867.900E 

2189 665.000N; 853.350E 

2193 659.850N; 848.150E 



Rock Name 


Quartz Plagioclase 


K -Feldspar 


Biotite 


Muscovite 


Epidote 


Garnet 


Opaques Sericite 


Biotite Gneiss 


34.6 


28.2 


18.8 


13.8 


2.6 


0.4 


0.0 


0.6 1.0 


Biotite Gneiss 


57.0 


12.0 


25.8 


3.2 


0.8 


0.4 


0.2 


0.4 0.2 


Biotite Gneiss 


26.4 


29.6 


24.2 


15.4 


4.2 


0.2 


0.0 


0.0 0.0 


Average 


39.3 


23.3 


22.9 


10.8 


2.5 


0.3 


0.1 


0.3 0.4 


Minimum 


26.4 


12.0 


18.8 


3.2 


0.8 


,0.2 


0.0 


0.0 0.0 


Maximum 


57.0 


29.6 


25.8 


15.4 


4.2 


0.4 


0.2 


0.6 1.0 


StdDev 


15.8 


9.8 


3.7 


6.6 


1.7 


0.1 


0.1 


0.3 0.5 



the Ashe Metamorphic Suite and thus, its stratigra- 
phic position with respect to other map units cannot 
be determined from the surface geologic map. 

In the type area, the protolith of the Richard 
Russell Formation originated from clastic sedi- 
ments (Gillon, 1982). In the Canton Quadrangle, 
the high feldspar content of some biotite gneisses 
may indicate a felsic volcanic component also. The 
interlayered amphibolites undoubtedly have a mafic 
volcanic origin, perhaps as tuffs or thin flows or 
sills. 



mation occurs at the intersection of SR 1394 and 
SR 1390, the road along Sugar Creek. Other good, 
easily accessible exposures are along SR 1401 for 
about 0.4 miles west from Earlies Gap. Nearly 
continuous bedrock exposures occur in the head- 
water streams of North Turkey Creek, in the steep 
drainages on Pinnacle Knob, and in the small, but 
steep stream channels that drain the ridge that 
trends southwest from Earlies Gap. In the Canton 
Quadrangle good exposures occur in the small 
steep stream valleys on the sides of Doubleside 
Knob. 



Earlies Gap Biotite Gneiss 

FIELD OCCURRENCE AND DESCRIPTION 

The Earlies Gap Biotite Gneiss crops out 
over much of the northern half of the Canton 
Quadrangle and continues in a two-mile-wide band 
through the eastern half of the Sandymush Quad- 
rangle. This two-mile-wide band is designated as 
the type area and contains most of the good acces- 
sible exposures discussed below. The type locality 
is in Buncombe County along the south side of SR 
1394 west of its intersection with SR 1401. (The 
abbreviation, SR, is used in this report for Secon- 
dary Road; see figure 3 for location of Secondary 
Roads.) This exposure, an extensive road cut in the 
vicinity of Payne Chapel, typifies the distinctly 
layered, heterogeneous, migmatitic, folded, and 
highly jointed character of the map unit (see figure 
5). 

Smaller, isolated outcrops are characterized 
and dominated by any one or more of these fea- 
tures. Another exposure representative of the for- 



The Earlies Gap Biotite Gneiss is a se- 
quence, at least 4,000 feet thick, of well foliated, 
highly layered biotite gneiss. It is interlayered with 
thinly layered amphibolite, layered biotite granitic 
gneiss, and rare calc-silicate granofels or musco- 
vite-biotite gneiss. The interlayering occurs at all 
scales from hand sample to outcrop to map scale. 
The Earlies Gap Biotite Gneiss is characterized by 
a diagnostic wavy foliation and thin layers of 
coarse-grained biotite flakes. The wavy foliations 
vary in thickness from about one millimeter to 
about a centimeter. 

Rocks of the Earlies Gap Biotite Gneiss are 
locally migmatitic, most notably in the Canton 
Quadrangle near the southern end of the outcrop 
belt. The leucocratic neosome, composed chiefly 
of quartz and feldspar, commonly crosscuts the 
gneissic foliation. Locally, the migmatitic areas 
show the effects of later shearing and folding. 
Mylonites also occur in the Earlies Gap. 

Biotite gneiss, the dominant rock type, var- 
ies in color from very light gray to medium light 
gray; its color reflects the biotite content; that is, 



10 




Figure 5. Earlies Gap Biotite Gneiss. Above, Medium- to 
thick-layered biotite gneiss. Three-foot-thick amphi- 
bolite is left of hammer. Outcrop is 500 feet southwest 
of Payne Chapel along SR 1394. Below, Well-foliated, 
distinctly layered biotite gneiss with abundant, highly 
wrinkled schistose layers. Pencil, upper center, is 6 
inches long. Outcrop is 0.3 miles northeast of Payne 
Chapel along SR 1394. 



the higher the biotite content, the darker the rock. 
It is well foliated on a millimeter to a centimeter 
scale. Layering ranges from centimeters to meters 
in thickness. As the biotite content increases, the 
foliation and layering become thinner and the 
gneissic character of the rock becomes more schis- 
tose. Interlayered with the biotite gneisses are thin 
repetitive layers of amphibolite and lesser calc- 
silicate granofels. The amphibolite is commonly 
retrograded, thereby making some thin amphi- 
bolites difficult to distinguish from biotite gneiss. 

Amphibolite is the second most abundant 
rock type in the Earlies Gap Biotite Gneiss, occur- 
ring as thin layers, lenses, and pods. They range in 
thickness from a few millimeters to meters and are 
interlayered at all scales with the biotite gneiss. To 
the northeast, on the Sandymush Quadrangle, 
amphibolite crops out extensively and dominates 
at most exposures. This area is mapped as an 
amphibolite-dominant phase and underlies about 
five percent of the quadrangle. Keith (1904) too, 
indicates abundant amphibolite in this area and 
shows it extending on to the northeast under the 
now abandoned term "Roan Gneiss". Several other 
smaller amphibolite-dominated areas are also 
mapped on both the Sandymush and Canton Quad- 
rangles. 

Good exposures of amphibolite are uncom- 
mon because of the rapid weathering of the domi- 
nant mafic layers in this unit. The best exposures 
occur along SR 1394, approximately one-half mile 
south of Canto on the Sandymush Quadrangle. 
Other good exposures occur on the northern slopes 
of High Knob near the eastern edge of the quad- 
rangle. Interlayered calc-silicate granofels is much 
less abundant than amphibolite and occurs as pod- 
like masses. 



PETROGRAPHY 

In thin section, biotite gneiss exhibits a 
lepidoblastic to equigranular granoblastic texture. 
Lepidoblastic textures dominate as this unit has a 
high biotite content. Locally, mylonitic textures 



11 



are common. Modal analyses of various samples 
are given in table 4. 

The felsic portion of the biotite gneiss ranges 
between tonalitic and granitic with the bulk of the 
felsic layers being granodioritic in composition 
(figure 6). The biotite content, naturally, is highest 
in the more schistose layers. The biotite content of 
these interlayers is estimated at over 80 percent. 
Rare pleochroic halos occur in the biotite. 

Muscovite occurs in very minor amounts in 
the gneiss. Field observations indicate that the 
muscovite content increases ever so slightly in the 
southeastern outcrop area of the Canton Quad- 
rangle. 

Amphibolite is equigranular nematoblastic 
in texture, but grades to lepidoblastic where retro- 
gressive metamorphism has been thorough. It is 
poorly foliated to well foliated depending partly on 
the proportion of amphibole present and partly on 
the thoroughness of retrogression. The higher the 
amphibole content, the better developed the folia- 
tion. The more thorough the retrogression, the 
higher the biotite content and the more distinct the 
foliation. 

Calc-silicate granofels is equigranular gra- 
noblastic to lepidoblastic, massive to foliated, thin 
layered to podiform. It is commonly interlayered 
and mapped with amphibolite. Only two small 
bodies of calc-silicate granofels are separately 
mapped within the Earlies Gap Biotite Gneiss. 
They both occur along North Turkey Creek near 
the eastern edge of the Sandymush Quadrangle. 
Calc-silicate granofels consists of plagioclase, K- 
feldspar, quartz, epidote-group minerals, diopside, 
and other alteration minerals. Characteristically, 
the diopside weathers rapidly to diagnostic spots of 
yellowish-brown limonite. 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

An absolute age for the Earlies Gap Biotite 



Gneiss has not been determined in the study area. 
Reconnaissance observations indicate the forma- 
tion interfingers and correlates with rocks to the 
north and northeast on the Marshall, Mars Hill, and 
Barnardsville Quadrangles. It correlates well with 
portions of a biotite-hornblende migmatite unit on 
the Mars Hill Quadrangle (Merschat, 1977) whose 
granitic interlayers are dated at 1214 ± 83 million 
years (Fullagar et al., 1979; Rankin, 1983). It also 
correlates well with some of the biotite-rich por- 
tions of the biotite granitic gneiss unit of the Mars 
Hill Quadrangle (Merschat, 1977). These rocks 
have an age of 1270 ± 44 million years (Fullagar, 
1983). The Earlies Gap Biotite Gneiss may indicate 
downstrike lithologic changes resulting from origi- 
nal variations of the protolith and from a more thor- 
ough retrogression of some mafic rocks. The 
Earlies Gap Biotite Gneiss is a little less felsic than 
most of the biotite granitic gneiss unit of the Mars 
Hill Quadrangle. It is less mafic than the amphi- 
bolitic basement complex of the intervening 
Marshall Quadrangle (Brewer, 1986), and also less 
mafic than the biotite-hornblende migmatite unit 
of the Mars Hill Quadrangle. Based on the above 
described relations, the Earlies Gap Biotite Gneiss 
is most likely a Middle Proterozoic unit with an age 
of about 1.2 to 1.3 billion years. 

The contact between the Earlies Gap Biotite 
Gneiss androcks of the Ashe Metamorphic Suite is 
the Holland Mountain thrust fault. This contact is 
readily mapped on the basis that muscovite and 
aluminous minerals are virtually absent from the 
Earlies Gap Biotite gneiss, but are very common in 
the Ashe Metamorphic Suite. The presence or 
absence of muscovite and aluminous minerals 
makes this boundary one of the most easily distin- 
guished contacts in the central Blue Ridge of western 
North Carolina. The contact between the Earlies 
Gap Biotite Gneiss and the Sandymush Felsic 
Gneiss is gradational in nature. Both formations 
contain similar rock types, thereby making the 
correct formational assignment of individual 
samples or some small outcrops uncertain. 

The protolith for the Earlies Gap Biotite 
Gneiss is thought to have been a thick accumula- 



12 



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tion of rapidly repeating thin mafic and felsic 
volcanic rocks. The well developed layering char- 
acteristic of the dominant biotite gneiss suggests a 
well layered protolith. The low quartz content 
tends to preclude a sedimentary origin, although 
rare interlayers of metasedimentary rock may exist 
locally. 



Sandymush Felsic Gneiss 

FIELD OCCURRENCE AND DESCRIPTION 

The Sandymush Felsic Gneiss extends di- 
agonally across the Sandymush Quadrangle and 
the northwest corner of the Canton Quadrangle. It 
underlies approximately 50 square miles of the two 
quadrangles. The type locality is on the south side 
of N.C. Highway 63 about 2,000 feet west of the 
confluence of Sandymush Creek and Little San- 
dymush Creek. Other easily accessible exposures 
are along SR 1394 from where Sugar Creek joins 
Sandymush Creek west to Clark Branch. The best 
exposures, however, occur in the steep valleys of 
small headwater tributary streams of Sandymush, 
Little Sandymush, and Willow Creeks. 

The Sandymush Felsic Gneiss is a monoto- 
nous, repetitive sequence of layered rocks perhaps 
more than 15,000 feet thick. It consists dominantly 
of biotite granitic gneiss to quartz dioritic gneiss 
interlayered and intergraded with biotite gneiss, 
biotite schist, amphibolite, and very minor calc- 
silicate granofels. These various lithologic types, 
except calc-silicate granofels, are widespread and 
common throughout this heterogeneous map unit. 

Biotite granitic gneiss to quartz dioritic gneiss 
layers are dominant. The other lithologic types are 
so interlayered, intergraded, and thin that they can 
be mapped as separate units in only a few areas. 
The thickness of biotite granitic- to quartz dioritic 
gneiss layers is variable. At some outcrops the 
layering is measured in millimeters, at others in 
centimeters, and at still others in meters. As the 
biotite content increases, the rock becomes schis- 
tose. Grain size varies from coarse to fine. The 



texture is equigranular, but where there has been 
local mylonitization it is inequigranular. Fresh 
color ranges from very light gray to very pale 
orange to medium light gray. The weathered color 
generally reflects the amount and degree of iron 
oxide staining. The felsic gneiss layers are repeat- 
edly interlayered with amphibolite layers, many of 
which are very thin. Most amphibolite layers are 
continuous at the hand sample and outcrop scale, 
but are discontinuous at map scale (figure 7). 

Locally, the thin amphibolite interlayers are 
retrograded. These retrograded layers have a high 
biotite content which makes them difficult to dis- 
tinguish from other biotite-rich layers. 

Calc-silicate granofels is relatively rare, but 
where observed it is associated and interlayered 
with amphibolite. The calc-silicate layers occur 
discontinuously and are abundant enough to distin- 
guish separately at map scale only in one area along 
Willow Creek on the Sandymush Quadrangle. 

Rocks of the Sandymush Felsic Gneiss are 
very locally migmatitic. The neosome consists of 
quartz and feldspar and commonly crosscuts the 
gneissic layering. 



PETROGRAPHY 

The felsic layers have compositions ranging 
from quartz-rich granitoid to quartz diorite or tonal- 
ite but the majority have a granitic composition. 
The chief texture exhibited in the felsic layers is 
granoblastic or lepidoblastic depending on the 
biotite mica content. The dark colored, low-felsic 
bands have a high biotite content and are strongly 
lepidoblastic. Modal compositions are shown in 
table 5. 

Amphibolites are very abundant within the 
Sandymush Felsic Gneiss. They occur as layers, 
lenses, and pods that vary in thickness from a few 
millimeters to meters. In several areas they are 
abundant enough to be mapped as separate units. 
Nematoblastic texture is dominant. 



14 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

The Sandymush Felsic Gneiss is one of the 
oldest rock units on the maps. Although not dated 
in the local area, it correlates with rocks to the 
northeast that have been dated radiometrically. 
The Sandymush Felsic Gneiss correlates at least in 
part with either the biotite-hornblende migmatite 
or the layered biotite granitic gneiss units of the 
Mars Hill Quadrangle (Merschat, 1977) and the 
amphibolitic basement complex of Brewer (1986). 
Granitic gneiss layers from the biotite-hornblende 
migmatite unit have an age ofl214±83 million 
years (Fullagaretal., 1979; Rankin, 1983). Granitic 
gneiss layers from the biotite granitic gneiss unit 
yield an age of 1270 ± 44 million years (Fullagar, 
1983). The Sandymush Felsic Gneiss of the San- 
dymush and Canton Quadrangles is a little more 
felsic and less mafic than equivalent units to the 
north and northeast. The mafic layers are thinner, 
less abundant, and more altered than those of the 
Mars Hill Quadrangle. Many of the mafic rocks in 
the Mars Hill Quadrangle still contain relic miner- 
als and textures indicative of granulite grade meta- 
morphism. It is possible that the mafic character of 
rocks in the Sandymush and Canton Quadrangles 
was somewhat altered or obliterated by Paleozoic 
metamorphism. The amphibolites are mostly retro- 
gressed to biotite gneisses and schists, thereby 
producing the apparent change in present character 
of these rocks to the southwest. 

The boundary between the Sandymush Fel- 
sic Gneiss and the Earlies Gap Biotite Gneiss is a 
gradational stratigraphic contact. Felsic gneiss, 
including biotite granitic gneiss to quartz dioritic 
gneiss, dominates in the Sandymush Formation. In 
contrast, biotite gneiss dominates in the Earlies 
Gap. The disappearance of both coarse-grained 
biotite and the characteristic wavy foliation sur- 
faces of the Earlies Gap help mark the boundary 
between it and the Sandymush Felsic Gneiss. To 
the northwest, the Spring Creek Granitoid Gneiss 
and the Doggett Gap Protomylonitic Granitic Gneiss 
are thought to be intrusive into the Sandymush 
Felsic Gneiss. However, the original relations are 



clouded by widespread transposition and myloniti- 
zation which mask and modify the true nature of 
the contacts. 

The protolith for the Sandymush Felsic 
Gneiss was likely a thick plutonic-volcanic se- 
quence of rocks. Felsic material dominated, in 
contrast to the mixed mafic and felsic volcanic 
protolith of the Earlies Gap Gneiss. 



Spring Creek Granitoid Gneiss 

FIELD OCCURRENCE AND DESCRIPTION 

The Spring Creek Granitoid Gneiss crops 
out in the northwest part of the Sandymush Quad- 
rangle. It covers approximately 20 percent of the 
quadrangle. The type locality is along N.C. High- 
way 63 west of Doggett Gap where there are 
intermittent roadside exposures for approximately 
0.8 of a mile. The exposures start approximately 
0.4 of a mile northwest of Doggett Gap and con- 
tinue along the highway to the vicinity of Mt. 
Pleasant Church. Other typical exposures are along 
N.C. Highway 209 in the northwesternmost corner 
of the Sandymush Quadrangle and the adjoining 
Spring Creek Quadrangle. 

The Spring Creek Granitoid Gneiss, at the 
very least 4,000 feet thick, is composed primarily 
of coarse-grained biotite granitic gneiss (figure 8). 
Also present are interlayers of layered biotite 
granitic gneiss, protomylonitic to mylonitic grano- 
dioritic gneiss, amphibolite, and rare calc-silicate 
granofels. 

The coarse-grained biotite granitic gneiss is 
light gray, mottled with pinkish gray to pale red- 
dish brown. The gneiss is poorly foliated to foli- 
ated. Most outcrops exhibit very thick to medium 
layering. The coarse-grained biotite granitic gneiss 
makes up about 60 percent of the formation. 

Layered biotite granitic gneiss is similar to 
the coarse-grained biotite granitic gneiss, except it 
is more highly foliated and exhibits less massive 



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17 



layering. These interlayered gneisses make up 
about 20 percent of the Spring Creek Granitoid 
Gneiss. 

Protomylonitic to mylonitic granodioritic 
gneiss interlayers occur throughout the formation. 
The mylonitic interlayers do not appear to be 
concentrated in local areas or associated with major 
regional structures. These layers are well foliated 
and are mostly thin to thick layered. Much of the 
mylonitic gneiss is porphyroclastic, but the por- 
phyroclasts are much smaller than those in the 
Doggett Gap Protomylonite. The porphyroclasts 
range from about 0.5 centimeter to 1 centimeter in 
size. These mylonitic rock types make up approxi- 
mately 15 percent of the Spring Creek Granitic 
Gneiss. 



analyses are listed in table 6. 

The interlayered biotite granitic gneiss is 
distinguished from the granitic gneiss by its better 
developed lepidoblastic texture and its higher bi- 
otite content. * 

Amphibolites of the Spring Creek Granitoid 
Gneiss are equigranular nematoblastic in texture. 

The calc-silicate granofels layers have an 
equigranular granoblastic to nematoblastic tex- 
ture. They consist of plagioclase, K-feldspar, 
amphibole, epidote-group minerals, and other 
accessory minerals including biotite, sphene, and 
opaques. 



Amphibolite occurs as thin interlayers in the 
Spring Creek Granitoid Gneiss. In only one small 
area in the Sandymush Quadrangle are the interlay- 
ers abundant enough to distinguish as a mappable 
subunit. The amphibolite is dark greenish gray to 
greenish black, containing mostly hornblende and 
plagioclase. The rocks are foliated, especially 
where retrogression has been most intense. Am- 
phibolite makes up approximately four percent of 
this unit. 

Calc-silicate granofels interlayers occur, but 
are quite rare. Where observed in the field, they 
occur with amphibolites in layers and pods. Calc- 
silicate granofels is very light gray to greenish gray 
in color on fresh surfaces, and is massive to slightly 
foliated with thin to thick layering. Locally it 
grades into amphibolite. Calc-silicate granofels 
layers make up about one percent of the outcrop 
area. 



PETROGRAPHY 

The coarse-grained granitic gneiss of the 
Spring Creek exhibits an equigranular granoblastic 
texture to an inequigranular lepidoblastic texture. 
Locally, mylonitic textures are observable. The 
gneiss has the composition of a granite. Modal 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

The absolute age of the Spring Creek Grani- 
toid Gneiss is not precisely known as no attempt 
has yet been made to date the formation. The area 
underlain by the Spring Creek was included in the 
extensive Cranberry Granite of Keith (1904). It is 
now correlated with or included in the Elk Park 
Plutonic Suite (Rankin et al., 1972, 1983), the 
Cranberry granitic basement complex of Brewer 
(1986), and the biotite granitic gneiss of the 1985 
Geologic Map of North Carolina (N.C. Geological 
Survey). Collectively, this large granitic rock unit 
is approximately 1.1 billion years old (Fullagar 
and Odum, 1973; Fullagar et al., 1979; Fullagar, 
1983). 

The Spring Creek Granitoid Gneiss is con- 
sidered to be intrusive into the Sandymush Felsic 
Gneiss. However, the contact is not well exposed 
and is commonly overprinted by mylonitization 
and thus its true nature is not obvious. A magmatic 
origin for the Spring Creek is suggested by its 
massive, very thick to thick layering, weak folia- 
tion, and granitic composition. Rocks of the Spring 
Creek Granitoid Gneiss may represent an intrusive 
pluton within the very complex and multi-origin 
basement complex of western North Carolina. 



18 




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19 



Doggett Gap Protomylonitic Granitoid Gneiss 

FIELD OCCURRENCE AND DESCRIPTION 

The Doggett Gap Protomylonitic Granitoid 
Gneiss forms two narrow bands in the northwest 
quarter of the Sandy mush Quadrangle. The largest 
band is about 5 miles long and 1 mile wide. The 
smaller band is folded and is about 5.5 miles long 
and from 0.5 to 0. 1 mile wide. North Carolina 
Highway 63 cuts across the largest band at Doggett 
Gap and this section is designated the type locality. 
Outcrops along the road occur intermittently for 
about 0.4 mile west of the gap and 0.7 mile east of 
the gap. Other exposures in the type area occur 
both northeast and southwest of Doggett Gap in the 
grass fields and pastures along a northeast-trending 
ridge. This two and one-half mile-long ridge 
extends from Robinson Rough in the southwest to 
Mikes Knob in the northeast. These outcrops are 
dominated by very coarse-grained protomylonite 
that characterizes the Doggett Gap Protomylonitic 
Granitoid Gneiss. 

The Doggett Gap Protomylonitic Granitoid 
Gneiss is a sequence of mylonitized granitic rocks 
interlayered with biotite granitic gneiss, biotite 
tonalite gneiss, and amphibolite. It is approxi- 
mately 5,000 feet thick. The very coarse-grained 
granitic protomylonites which characterize the unit 
(figure 9) make up approximately 70 percent of the 
formation. 

The protomylonitic layers are distinctly 
megacrystic. They are light gray to medium light 
gray to very pale orange and are poorly foliated to 
well foliated. The layers range from medium to 
very thick. 

Biotite granitic gneiss to biotite tonalite 
gneiss interlayers are common, but are not very 
thick; layering varies from thin to medium. This 
lithologic type comprises about 25 percent of the 
entire map unit. 

Amphibolite of the Doggett Gap is present 
as thin interlayers to small, locally mappable bod- 



ies. At most places it is mylonitized and commonly 
shows the effects of retrogressive metamorphism. 

PETROGRAPHY 

Protomylonites of the Doggett Gap are ine- 
quigranular (megacrysts range from 0.5 centimeter 
to 4 centimeters), mylonitic, and poorly layered to 
layered. Layer thicknesses range from centimeters 
to meters. The composition of the characteristic 
protomylonites is granitic. Interlayers of biotite 
granitic gneiss to biotite tonalite gneiss are grano- 
blastic to lepidoblastic (table 7). 

The amphibolites are mostly medium- to 
coarse-grained, nematoblastic to weakly lepido- 
blastic, and commonly mylonitic. Retrogression is 
indicated by the common occurrence of biotite 
replacing hornblende. 



AGE AND CONTACT RELATIONSHIP 

A radiometric age for the Doggett Gap 
Protomylonitic Granitoid Gneiss has not been 
determined. The protolith of the Doggett Gap 
Protomylonitic Granitoid Gneiss is interpreted to 
have intruded its adjacent formations; the Spring 
Creek Granitoid Gneiss and the Sandymush Felsic 
Gneiss. It is thus presumed to be younger than both 
of these units. The Doggett Gap has also been 
affected by Middle to Late Proterozoic mylonitic 
deformation. Thus, the Doggett Gap Protomylo- 
nitic Granitoid Gneiss is reasoned to be latest 
Middle Proterozoic in age. 

Keith ( 1 904) recognized and mapped coarse- 
grained granitic rocks in this region as part of his 
Max Patch Granite. However, general differences 
in appearance and composition, along with uncer- 
tainties of cross- strike correlation of these various 
metamorphosed plutonic bodies have led subse- 
quent geologists to limit application of the term 
"Max Patch" to rocks in and around the type area 
(North Carolina Geological Survey, 1985). 

The Doggett Gap Protomylonitic Granitoid 



20 




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Gneiss may be equivalent to Brewer's (1986) Indian 
Grave metagranite mapped about ten miles to the 
northeast. However, the large mylonitic "eye" 
structures, or augen, in the Doggett Gap are not 
entirely monomineralic as in the Indian Grave 
metagranite. In the Doggett Gap, the augen are 
composed chiefly of coarse-grained granitic mate- 
rial. The equivalency, therefore, will remain un- 
certain until the area in between is more thoroughly 
mapped. Brewer (1986) tentatively correlated his 
Indian Grave unit with the Beech Granite of the 
Crossnore Suite. However, until further study, this 
correlation must be considered even more specula- 
tive. 



Talc Body 

FIELD OCCURRENCE AND DESCRIPTION 

Four small talc bodies occur in the north- 
west quarter of the Sandymush Quadrangle. The 
deposits are shown by Keith (1904) under the 
grouping "soapstone,dunite, and serpentine". These 
bodies are very small with exposures consisting of 
only a few small outcrops and some associated 
float material. Precise locations are listed in 
Appendix 3. The talc bodies are surrounded by 
granitic and layered granitic gneisses and are evi- 
dently isolated masses. They are not associated 
with amphibolite or any other altered mafic or 
ultramafic rock. They have a very pronounced 
foliation that may be related to Proterozoic mylo- 
nitization and to a subsequent, subparallel Taconic 
metamorphic overprint. The bodies appear to be 
podiform, possibly resulting from large-scale, ex- 
tensive boudinage. 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

The absolute age of the talc bodies is not 
known. Similar deposits are present northeastward 
through Madison County for at least twenty miles. 
The protolith for these talc bodies is uncertain. A 
sedimentary origin was suggested by Bentzen and 
Wiener (1973) based principally on a spatial asso- 
ciation with nearby marble layers. Bohannon (1975) 
proposed an intrusive origin, citing high trace- 
element values of nickel and chromium, indicating 
derivation from ultramafic igneous rock. In the 
Sandymush Quadrangle their apparent sharp con- 
tact with the surrounding granitic gneiss favors an 
intrusive origin. The talc bodies would thus be 
younger than the granitic gneiss host. Initially they 
may have been intruded as ultramafic rocks and 
later were altered to talc-rich bodies. This altera- 
tion may have happened during the Grenville 
metamorphic event, but it is unlikely. High-tem- 
perature Grenville metamorphism would have 
driven off most of the water needed for hydration 
and subsequent formation of talc. A more likely 
time for steatization was during the Late Proterozoic 
mylonitization event or possibly during Paleozoic 
metamorphism. 

Similar talc bodies do not occur within the 
Late Proterozoic Ocoee Supergroup, Grandfather 
Mountain Formation, or the Paleozoic strata in the 
nearby Valley and Ridge of East Tennessee. Thus, 
a Paleozoic age is doubtful and a Proterozoic age is 
more consistent with the known facts. 



Ashe Metamorphic Suite 



PETROGRAPHY 

No thin sections were made of these talcose 
rocks. Hand sample examination, however, shows 
they are composed primarily of talc and a little 
chlorite. The proportions are variable both within 
each body and from one body to the next, although 
talc is always the dominant mineral. 



The Ashe Formation was named by Rankin 
(1970) and subsequently retermed the Ashe Meta- 
morphic Suite by Abbott and Raymond (1984). 
The Ashe Metamorphic Suite is a mixed assem- 
blage of clastic sediments and mafic volcanic rocks. 
The dominant rock types in the Sandymush and 
Canton Quadrangles include two-mica schist, 
metagraywacke, and two-mica gneiss. Minor 
amphibolite and calc-silicate granofels are also 



22 



present. In these quadrangles, the Suite is divided 
into two major units, one in which schist domi- 
nates, and one in which metagray wacke and gneiss 
dominate (figures 10 - 12). 



SCHIST 

Field Occurrence and Description — The 

schist-dominated unit underlies the southeast cor- 
ner of the Sandymush Quadrangle and four areas 
on the Canton Quadrangle. The northernmost area 
on the Canton Quadrangle is an extension of the 
outcrop area on the Sandymush Quadrangle. This 
area is allochthonous and separated from the main 
body of the Ashe Metamorphic Suite. It covers 
about five percent of the two quadrangles. An- 
other, much smaller allochthon is in the center of 
the Canton Quadrangle. It is about 1.5 miles long 
and averages about 0.2 mile wide. The largest area 
of Ashe schist forms an irregularly shaped band 
that runs diagonally through the Canton Quad- 
rangle from its northeast corner to its southern and 
western borders. This large area covers about 35 
percent of the Canton Quadrangle. The fourth area 
of schist is in the southwest corner of the quad- 
rangle and extends into the adjoining Clyde Quad- 
rangle. It too, is allochthonous and covers about 
three square miles. 

The most accessible exposures are found 
near the west border of the Canton Quadrangle 
along Crabtree Road, from approximately 0.5 mile 
to 1.0 mile southeast of Crabtree Gap. The best 
exposures occur along the crest and sides of Hol- 
land Mountain. Good exposures also occur along 
the southwest side of Newfound Mountain be- 
tween Big Butt Mountain and Rockyface Moun- 
tain, and along the southeast slopes of Buck Cove 
Mountain. 

The Ashe schist unit is characterized by 
muscovite-biotite schist which underlies more than 
60 percent of the outcrop area. The muscovite- 
biotite schist is light gray to medium light gray and 
is thin to medium layered. Kyanite or sillimanite is 
a key accessory mineral depending on metamor- 



phic grade. All schist layers are variably garnetif- 
erous and sulfidic. Repetitively and variably inter- 
layered with the schist is metagraywacke, musco- 
vite-biotite gneiss to biotite gneiss, amphibolite, 
and rare calc-silicate granofels. All rock types may 
be mylonitic or migmatitic in local areas. 

Interlayered metagraywackes are medium 
light gray to medium gray, and are commonly 
medium to thick layered. Any original sedimen- 
tary features have been obliterated or transposed. 
The metagraywackes are distinguished from the 
muscovite-biotite gneisses chiefly by their higher 
quartz and lower feldspar content. Metagray- 
wackes make up about 20 percent of the map unit. 
However, in only two areas are metagraywackes 
abundant enough to distinguish as a sub-unit on the 
geologic map (see plate 2). 

Interlayers of muscovite-biotite gneiss to 
biotite gneiss are medium gray to medium dark 
gray. Layering varies from medium to thick. 
These mica gneiss interlayers make up approxi- 
mately 15 percent of the Ashe schist. 

Widely scattered amphibolite interlayers 
occur in the Ashe schist. They are dark greenish 
gray to greenish black and thin layered and are 
rarely, if ever, interlayered with calc-silicate gran- 
ofels. They make up less than five percent of the 
outcrop area. Only two areas are extensive enough 
and contain sufficient amphibolite interlayers to be 
mapped separately. These areas are on the south- 
east side of Potato Knob near the south border of 
the Canton Quadrangle and about 0.4 mile south of 
Newfound Gap. 

The thin-layered calc-silicate granofels that 
occur within the Ashe schist are calcareous 
metagraywackes. They have the appearance of 
metagraywacke, but have a very high quartz con- 
tent. In addition, garnet and an amphibole mineral 
are invariably present. 

Petrography — The Ashe schists are me- 
dium- to coarse-grained, finely foliated micaceous 
rocks that exhibit a strong lepidoblastic texture. 



23 



The schists are variably porphyroblastic 
ranging from to 15 percent. The porphyroblasts 
are of garnet and kyanite and are commonly 
poikiloblastic. Kyanite porphyroblasts are occa- 
sionally kinked, while the garnets are commonly 
fractured. Where sillimanite replaces kyanite, the 
porphyroblastic character of the schists disappears. 

The mineral composition of the Ashe schist 
is quite variable over the map or even across an 
outcrop. For example, there are garnet-muscovite- 
biotite schists, garnet-kyanite-muscovite-biotite- 
schists, garnet-sillimanite-kyanite-muscovite-bi- 
otite schists, garnet- sillimanite-muscovite-biotite 
schists, and sillimanite-biotite schists. The mineral 
composition of several samples is shown in table 8. 

Metagraywacke layers are weakly foliated 
and exhibit a granoblastic to lepidoblastic texture. 
The higher the original clay content, the greater the 
mica content and the better developed the lepido- 
blastic texture. The composition of the metagray- 
wacke in the Ashe schist is quite variable. 



GNEISS 

Field Occurrence and Description — The 

gneiss-dominated map unit of the Ashe Metamor- 
phic Suite is present in the southeast part of the 
Canton Quadrangle. It underlies about 15 percent 
of the quadrangle. The best and most accessible 
exposures occur in road cuts on the north side of 
Interstate-40 from approximately 0.3 mile to 1 mile 
west of the Buncombe-Haywood County line. 

Metagraywacke is the dominant rock type 
followed by mica gneiss. Typically, the metagray- 
wacke contains over 50 percent quartz. Mica 
gneiss, ranging from muscovite-biotite gneiss to 
biotite gneiss, contains less quartz, but is higher in 
feldspar and a little higher in micaceous minerals. 
The rock types grade into each other with fresh 
samples being difficult to distinguish because of 
the similarity of quartz and feldspar grains. How- 
ever, weathering accentuates the feldspar by caus- 
ing it to lighten in color, thereby making it feasible 
to make accurate field classifications. 



Mica gneiss, ranging from muscovite-bi- 
otite gneiss to biotite gneiss, is interlayered through- 
out the schist unit. The gneiss is weakly foliated to 
foliated and exhibits a granoblastic to lepidoblastic 
texture. It is very similar in appearance to the 
metagraywackes and is distinguished on the basis 
of a higher feldspar-to-quartz ratio. As the mica 
content increases the lepidoblastic texture becomes 
better defined. One thin section analyzed yielded 
a tonalitic composition (see table 8, figure 10). 

Amphibolite layers within the Ashe schist 
are composed mostly of hornblende and plagio- 
clase. They appear to be similar in composition to 
those mapped in the biotite gneiss and schist unit 
and the biotite-plagioclase-quartz gneiss unit of the 
adjoining Cruso Quadrangle (Morrow, 1977). 

Rare calc-silicate granofels found in the 
Ashe schist are similar to those described by Morrow 
(1977) in his biotite gneiss and schist unit. The 
calc-silicate rocks are composed mostly of quartz, 
feldspar, garnet, and either an amphibole or biotite. 



The Ashe gneiss contains approximately 50 
percent metagraywacke. Metagraywacke is light 
gray to medium dark gray on the fresh surface. The 
thickness of the layers ranges from a few centime- 
ters to several meters. The metagraywacke layers 
are commonly migmatitic. 

Interlayered with metagraywacke in the Ashe 
gneiss are muscovite-biotite gneiss to biotite gneiss, 
kyanite-garnet-muscovite-biotite schist, silli- 
manite-kyanite-garnet-muscovite-biotite schist, 
amphibolite, and calc-silicate granofels. Musco- 
vite-biotite gneiss to biotite gneiss is the second 
most abundant rock type, making up about 40 
percent of the map unit. 

Interlayered sillimanite-kyanite-garnet-mica 
schist makes up over five percent of the unit. It 
closely resembles other schists in the Ashe Meta- 
morphic Suite. 

Calc-silicate granofels is very sparingly 
present as thin layers and pods less than a meter in 



24 




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Figure 11. Ashe Metamorphic Suite, Schist unit (on facing 
page, left side). Above, Mica schist with abundant 
porphyroblasts of muscovite up to 4 centimeters across. 
Tip of pencil points to one porphyroblast. Below, 
Kyanite-garnet schist. Several lath-like kyanite por- 
phyroblasts, up to 2 centimeters long, and numerous 2- 
to 3-millimeter garnets are present on foliation sur- 
faces. Exposures are along private road near Beaver- 
dam Creek, 0.6 miles southwest of Beaverdam School, 
Canton Quadrangle. 



thickness. Calc-silicate granofels is composed 
mostly of quartz, plagioclase, garnet, and either 
hornblende or biotite. 



Petrography — Throughout the Ashe 
gneiss, lepidoblastic texture dominates, but a gra- 
noblastic texture is also common, especially in the 
metagraywacke layers (figure 12). 

The mica gneiss layers differ principally in 
feldspar and quartz content from the metagray- 
wacke layers. In metagraywacke, quartz is more 
abundant; in the gneiss, feldspar is prevalent. In 
both types biotite is generally more abundant than 
muscovite. Modal analyses are given in table 9. No 
modal analyses were made of the interlayered 
schist or calc-silicate granofels. Hand sample 
examination, however, indicates they are very 
similar to schist and calc-silicate granofels else- 
where in the Ashe Metamorphic Suite. 



AGE AND CONTACT RELATIONSHIP 

The most frequently cited age for the Ashe 
Metamorphic Suite is Late Proterozoic or Late 
Precambrian. This assignment is supported by 
stratigraphic correlation with the Lynchburg-Ca- 
toctin sequence of Virginia (Rankin, 1970). Zir- 
cons from the Catoctin and presumed correlative 
units have been dated by Rankin et al. ( 1 969) at 820 



Figure 12. Ashe Metamorphic Suite, Gneiss unit (on facing 
page, right side). Above, Metagraywacke with light- 
colored quartz-rich layers and thin, dark-colored bi- 
otite-bearing layers. Outcrop is 0.5 miles west of the 
Haywood-Buncombe County line along Interstate-40. 
Below, Photomicrograph of metagraywacke showing 
weakly developed lepidoblastic texture. Quartz (Qtz), 
some with undulatory extinction, dominates. Plagio- 
clase (PI), biotite (Bt), and opaques (Opq) also com- 
mon. Crossed polarizers, sample 1946. 



million years. Another age constraint is provided 
by relations with the Bakersville Gabbro. A whole 
rock Rb/Sr isochron from eight Bakersville dikes 
is 734 ± 24 million years (Goldberg et al, 1986). 
Field relations show that the Bakersville does not 
intrude the Ashe. This evidence suggests that the 
Ashe is younger than 734 million years. Numer- 
ous granitoid plutons intrude the Ashe in the South- 
ern Blue Ridge (North Carolina Geological Sur- 
vey, 1985) and thereby limit the minimum age. 
The Whiteside, Looking Glass, and Pink Beds 
plutons have Rb/Sr whole rock isochrons of about 
390 million years. The Rabun Gneiss also intrudes 
the Ashe and is assigned an age of 450-500 million 
years (Fullagar, 1983). However, zircon-based 
ages obtained by T.W. Stern of the U.S. Geologi- 
cal Survey are 373-351 million years (A.E. Nel- 
son, written communication, 1988). Alaskites and 
pegmatites also intrude the Ashe and are 390 to 435 
million years old. Metamorphism, dated at 470- 
430 million years (Butler, 1973) has affected the 
Ashe Suite. The Ashe is therefore younger than 
734 million years and no more recent than Early or 
Middle Ordovician. Consequently, a Late 
Proterozoic age is accepted for the unit. 

The schist unit of the Ashe Metamorphic 
Suite overlies Middle Proterozoic rocks along the 
Holland Mountain thrust fault. 

The internal boundary between the schist 
unit and the gneiss unit is evidently a normal 



Table 9. Modal analyses (in percent ), Gneiss unit of the Ashe Metamorphic Suite 

Sample No. N.C. Coordinates Rock Name Quartz Plagioclase K-Feldspar Biotite Muscovite Epidote Garnet Opaques 

1946 659.850N; 874.500E Metagraywacke 51.4 16.0 9.8 12.2 9.8 0.4 0.0 0.4 

2318 672.700N; 877,1 50E Metagraywacke 55.8 33.2 0.0 8.6 0.8 0.4 0.6 0.6 

2325 672.000N; 871.500E Metagraywacke 37.0 39.4 0.0 20.4 0.0 0.4 1.2 1.6 



Average 
StdDev 



48.1 
9.8 



29.5 
12.1 



3.3 

5.7 



13.7 
6.0 



3.5 

5.4 



0.4 
0.0 



0.6 

0.6 



0.9 

0.6 



27 



depositional, stratigraphic contact. This contact is 
somewhat arbitrarily located because both units 
are composed of very similar rock types. In the 
field, the unit assignment is based on whether 
schist dominates or metagray wacke to mica gneiss 
dominates. 

The upper limit of the Ashe Suite is not 
present in the Sandy mush or Canton Quadrangles. 
In the type area, the Ashe is conformably overlain 
by the Alligator Back Formation (Rankin et al., 
1973). 



Dunite 

FIELD OCCURRENCE AND DESCRIPTION 

No dunites crop out in the Sandymush Quad- 
rangle; however, eight small dunite bodies are 
present in the Canton Quadrangle. The two largest 
and best known are the Newfound Gap and Hom- 
iny Grove bodies (Pratt and Lewis, 1905; Hunter, 
1941). The Newfound Gap body is located a few 
hundred feet east of Newfound Gap along the 
Buncombe-Haywood County line. The Hominy 
Grove body is located near the Harmony Grove 
Church, approximately 400 feet west of the inter- 
section of SR 1609 with SR 1606. Smaller bodies 
occur in the vicinity of each of these larger bodies. 
A small dunite body occurs 600 feet north of 
Newfound Gap. An additional tiny body, too small 
to show at map scale, crops out about 100 feet north 
of this body (Hirt, 1987). At Hominy Grove a small 
body is located about 2,000 feet west of the larger 
dunite body. 

Elsewhere in the quadrangle two small bodies 
are located west of Beaverdam Creek on the south- 
east slopes of Sassafras Ridge. Another small 
dunite body is located on the south side of Inter- 
state-40, approximately 2,000 feet from the west 
edge of the Canton Quadrangle. The last small 
dunite body crops out on the southeast side of the 
ridge between Wilson and West Coves, about 4,500 
feet northeast of the intersection of S R 1 6 1 3 and S R 
1619. 



Many of these small bodies are represented 
by only one or two outcrops. Their extent is 
determined by float materials and soil characteris- 
tics. Float materials include both olivine and the 
common hydrous alteration minerals such as talc, 
anthophyllite, and vermiculite. The dunites weather 
to a nickeliferous saprolite and a dark-red soil that 
contains residual chalcedonic fragments. 

All the dunites, except the one between 
Wilson and West Coves, are surrounded by Gren- 
ville-age rocks. The one exception, only a few 
hundred feet away from the Earlies Gap, is tectoni- 
cally emplaced into a mylonitized zone of the Ashe 
schist. The dunites normally occur very close to 
the contact between the Earlies Gap Biotite Gneiss 
and the overlying Ashe Metamorphic Suite. A 
similar relationship exists on the nearby Mars Hill 
(Merschat, 1977), Barnardsville (Merschat, in 
progress), and Leicester Quadrangles (Wiener, 
unpublished mapping). 

The dunites, where unaltered, are composed 
mostly of olivine (Fo 92 ). The unaltered dunite is 
pale olive to dusky yellow green and is dusky 
yellow when weathered. It is usually fine- to 
coarse-grained, granular, and locally friable. Black 
crystals and blebs of chromite also occur; however, 
they make up only one or two percent of the rock. 
The altered dunites are variably serpentinized. 
Hydrous alteration minerals that occur, other than 
serpentine minerals, include talc, anthophyllite, 
chlorite, tremolite, and vermiculite. Much of the 
hydrous alteration occurs along fractures in the 
olivine bodies and in tiny fractures that cut individ- 
ual grains. During serpentization magnetite is 
formed. This alteration has proven to be useful in 
mapping the extent of altered olivine bodies with a 
magnetometer (Hirt, 1987; Perez, 1979). 



PETROGRAPHY 

A thorough investigation of the dunites was 
not within the scope of this report and thus only 
hand samples were examined. However, numer- 
ous petrologic studies have been completed on 



28 



many similar dunite bodies in western North Caro- 
lina. Studies on the Newfound Gap deposit have 
been made by Palmer et al. (1977), Perez (1979), 
Penso ( 1981), and Hirt( 1987). They record samples 
containing various amounts of olivine, chromite, 
serpentine, anthophyllite, tremolite, talc, vermicu- 
lite, magnetite, and chlorite. 



AGE AND CONTACT RELATIONSHIP 

The age of the dunites is not known conclu- 
sively. Dunites of the central Blue Ridge are most 
frequently placed within a broad range from Late 
Precambrian to Early Paleozoic (Hadley and Nel- 
son, 1971; North Carolina Geological Survey, 
1985). They have been metamorphosed during the 
Taconic, thereby restricting them to being Early 
Ordovician or older. Dunites do not occur in any 
Cambrian or Ordovician rocks of the nearby Val- 
ley and Ridge province, nor do they occur in the 
very Late Proterozoic Ocoee Supergroup or Grand- 
father Mountain Formation. Elsewhere in the Blue 
Ridge, dunites are present in the Ashe, Tallulah 
Falls, and Alligator Back Formations, all of Late 
Proterozoic age. Thus, the dunites probably origi- 
nated sometime during the 330-million-year span 
of the Late Proterozoic. 

The dunite bodies of the Canton Quadrangle, 
except one, occur in the Earlies Gap Biotite Gneiss. 
Their contacts with the Earlies Gap are covered. 
However, since better exposed western North 
Carolina dunites exhibit sharp contacts, it is ex- 
pected that contacts in the local area should also be 
quite sharp. 



Altered Mafic and Ultramafic Rock 

FIELD OCCURRENCE AND DESCRIPTION 

Two bodies of massive amphibolite and 
talc-bearing amphibolite crop out in Worley Cove 
in the northeast corner of the Sandymush Quad- 
rangle. The largest body occurs beneath a low 
ridge separating the two drainages that head up in 



Worley Cove to form Worley Creek. The smaller 
body occurs on the east side of the cove approxi- 
mately 3,000 feet north of the intersection of SR 
1110 with SR 1108. 

Both bodies lie within a large amphibolitic 
unit of the Earlies Gap Biotite Gneiss. The bodies 
are distinctive in that they are much more massive 
and contain a higher percentage of amphibole than 
the surrounding country rock amphibolites. In 
addition, talc, as pod-like alteration masses, occurs 
within each of these bodies and does not occur with 
the enclosing amphibolites. 



PETROGRAPHY 

In hand sample these rocks are greenish 
black to brownish black and are quite massive. 
They display a medium- to coarse-grained nema- 
toblastic texture. Compositionally they are over 90 
percent amphibole (hornblende) with lesser pla- 
gioclase and epidote-group minerals. The talc- 
bearing rocks are light greenish gray to greenish 
gray and are foliated. 



AGE, CONTACT RELATIONSHIP, AND PRO- 
TOLITH 

An absolute age is not available for the 
altered mafic and ultramafic rock unit. The unit 
must be younger than the amphibolites of the 
Earlies Gap Biotite Gneiss because it apparently 
intrudes them. The unit has been metamorphosed, 
thus requiring that it be older than the major meta- 
morphism that occurred in the Taconic. Most 
likely it is Middle Proterozoic to Early Paleozoic in 
age. 

The contact between these two rock bodies 
and the amphibolites of the Earlies Gap Biotite 
Gneiss is not exposed. Evidence suggesting that 
these bodies actually intrude the Earlies Gap Bi- 
otite Gneiss is their north to northwest trend which 
is oblique to trends in the country rocks. 



29 



These altered mafic and ultramafic rocks 
may represent any of the following intrusive rocks: 
gabbro, pyroxenite, or dunite. The talc pods may 
represent original compositional differences in the 
intrusion that were more susceptible to alteration. 



Snowbird Group 

FIELD OCCURRENCE AND DESCRIPTION 

The Snowbird Group underlies a small area 
along the western edge of the Sandymush Quad- 
rangle along the Buncombe-Madison County line. 
It covers less than five percent of the Sandymush 
Quadrangle and does not crop out in the Canton 
Quadrangle. The most easily accessible outcrops 
lie along Bald Creek. The best exposures, how- 
ever, are along the Buncombe-Madison County 
line for about one mile northeast of Little San- 
dymush Bald. 

In the Sandymush Quadrangle the Snowbird 
Group consists of an interlayered sequence of 
clastic metasedimentary rocks dominated by 
kyanite-garnet-mica schist and metagraywacke. 
Cross sections based on outcrop width and attitude 
of relic bedding suggest that 4000 feet of metasedi- 
ment are present. The schist layers make up over 
65 percent of the map unit. The schist is medium 
gray to medium dark gray on freshly broken sur- 
faces and it is thin to medium layered. At many 
exposures, relic bedding is indicated by composi- 
tional variations from layer to layer. 

Metagraywacke interlayers make up over 
30 percent of the formation. They are medium 
light gray to medium gray in color and are locally 
conglomeratic with granules and pebbles of both 
quartz and feldspar. Graded bedding was seen at 
only two outcrops. 

Calc-silicate granofels forms minor inter- 
layers within the metagraywacke. On fresh sur- 
faces these medium to thin layers are medium gray 
to dark gray. 



PETROGRAPHY 

The schist (figure 13) is finely foliated and 
has a pronounced lepidoblastic texture. Garnet and 
kyanite occur as porphyroblasts and exhibit a 
poikiloblastic texture. Some of the kyanite por- 
phyroblasts are as much as 1.5 centimeters in 
length. Kyanite is occasionally kinked and the 
garnet is commonly fractured. Mineral composi- 
tion of the schist is variable from sample to sample. 

Metagraywacke interlayers are poorly foli- 
ated to foliated and granoblastic to lepidoblastic in 
texture. This textural variation reflects the vari- 
ation in mica content which, in turn, reflects the 
clay content of the original sediment. Modal com- 
position of several samples is shown in table 10. 

Calc-silicate granofels in the Snowbird 
Group is a compositional and mineralogic vari- 
ation of metagraywacke. It has a granoblastic to 
nematoblastic texture. The more calcareous the 
original sediment, the more amphibole present and 
the better developed the nematoblastic texture. As 
noted during field traverses, mineral composition 
of the calc-silicate granofels is variable. 



AGE AND CONTACT RELATIONSHIP 

The metasedimentary rocks of the Little 
Sandymush Bald region are here assigned to the 
Late Proterozoic Snowbird Group of the Ocoee 
Supergroup. Previously they had been classed 
with other parts of the Ocoee — the Great Smoky 
Group (North Carolina Geological Survey, 1985; 
Hadley and Nelson, 1971) or the Great Smoky 
Conglomerate and Hiwassee Slate (Keith, 1904). 
There are several reasons for reassigning the rocks 
to the Snowbird. First, graded beds of metagray- 
wacke and graphitic schist or slate, very common 
in the Great Smoky, are rare to virtually absent in 
the Little Sandymush Bald area. Second, tourma- 
line, a very abundant, almost diagnostic accessory 
mineral in the Great Smoky (Hadley and Gold- 
smith, 1963), is only sparingly present in the rocks 
of the local area (figure 18 and Appendix 2). Third, 



30 











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at many nearby places it is the Snowbird that non- 
conformably overlies granitic "basement" rocks 
(Hadley and Goldsmith, 1963), just as is the case in 
the local area. 

In and around its type area, the Snowbird 
Group is a sequence of clastic marine sediments 
that were deposited directly onto granitic base- 
ment. In the nearby Pigeon River Gorge the Snow- 
bird Group is divided into four formations (Hadley 
and Goldsmith, 1963). The lowermost is the Wading 
Branch Formation followed by the Longarm Quartz- 
ite, the Roaring Fork Sandstone, and the Pigeon 
Siltstone. Insufficient data is available to warrant 
subdividing the Little Sandymush Bald rocks. 
However, because of their occurrence immedi- 
ately above the granitic basement and the domi- 
nance of dark-gray, fine-grained rocks, they are 
most likely correlative with the Wading Branch 
Formation. 

The lowermost contact, as previously dis- 
cussed, is a nonconformity. In the Sandymush 
Quadrangle, the Snowbird was deposited on an old 
erosion surface developed over the Spring Creek 
Granitoid Gneiss. The upper limit of the Snowbird 
is not present on the quadrangle. 



Mylonite itself is dense, compact to some- 
what flinty in texture, and locally approaches ul- 
tramylonite. The mylonites and protomylonites 
are interlayered with each other at the scale of 
centimeters. The mylonites are distinctive and are 
characteristic of the unit. «Many of the protomylo- 
nites closely resemble the interlayered gneiss. At 
many places gneiss, similar to the enclosing map 
unit, is interlayered with the mylonite and proto- 
mylonite. Thin interlayers of amphibolite and 
mylonitized amphibolite also occur within mylo- 
nite and protomylonite units. 



PETROGRAPHY 

No modal analysis was made of the mylo- 
nite and protomylonite. Hand samples are medium 
gray to dark gray on fresh surfaces; the more 
thorough the mylonitization the darker the color. 
Mylonitic to gneissic and variably porphyroclastic 
(less than 1 millimeter to 1 centimeter) textures are 
observable in hand sample. Mineralogic composi- 
tion of the mylonites reflects the map units from 
which they were derived. For example, mylonite 
derived from the aluminous Ashe Metamorphic 
Suite commonly contains abundant muscovite 
(figure 15). 



Mylonite and Protomylonite 

FIELD OCCURRENCE AND DESCRIPTION 

Mylonite and protomylonite, formed during 
Late Paleozoic deformation, is present at many 
places in the area. The larger, more continuous 
bodies are shown as separate units on the accompa- 
nying maps (plates 1 and 2). At many other more 
or less isolated exposures, mylonitic fabric over- 
prints the country rock to varying degrees. These 
places are shown on the maps by a colored pattern. 
Interestingly, almost none of the road cuts in the 
area contain exposures of mylonite. The most 
accessible outcrops are on the Canton Quadrangle 
and occur intermittently along slopes of the ridge 
separating West Cove from Wilson Cove. 



AGE AND CONTACT RELATIONSHIP 

The mylonites are Middle or Late Paleozoic 
in age. Locally, they obliterate or truncate the trace 
of the Holland Mountain thrust fault, crosscut unit 
boundaries, and truncate the Paleozoic foliation of 
the Ashe Metamorphic Suite and the Earlies Gap 
Biotite Gneiss. The truncation of the Paleozoic 
foliation and the Holland Mountain fault is most 
obvious around Williams Mountain and Big Butt 
Mountain in the northern part of the Canton Quad- 
rangle (see plate 2). The minimum age of the 
mylonite and protomylonite is uncertain, but re- 
gional considerations make it quite unlikely to be 
post-Paleozoic. 



32 



Trondhjemite 

FIELD OCCURRENCE AND DESCRIPTION 

Thin trondhjemite dikes and sills occur 
sparingly in the southeastern part of the Sandy mush 
Quadrangle and most of the Canton Quadrangle. 
They appear to be most abundant in the southeast 
half of the Canton Quadrangle where the Paleozoic 
metamorphic grade is highest. The dikes and sills 
range in thickness from several centimeters to a 
meter and are rarely traceable beyond the limits of 
a single outcrop. Nowhere in the study area are the 
bodies large enough to warrant mapping. 

In hand sample, trondhjemite is very light 
gray to medium light gray to very pale orange in 
color. It is unfoliated; however, a few samples 
show some alignment or streaking of minerals. 
This is attributed to original magmatic flow or may 
possibly record a weak deformation event. 



PETROGRAPHY 

Thin sections were not made of trondhjemite 
from the Sandymush and Canton Quadrangles. 
Samples of trondhjemite from nearby areas are 
somewhat varied (Yurkovich and Butkovich, 1982; 
Merschat, 1977; Morrow, 1977; Hadley and Gold- 
smith, 1963). Textures are porphyritic to grano- 
blastic and mortar structure is common. Grain size 
ranges from fine to medium grained. Modal analy- 
ses range from granodiorite to tonalite; however, 
most samples are tonalites. Plagioclase and quartz 
normally make up more than three-fourths of the 
rock. Minor biotite is present; K-feldspar and 
white mica rarely total more than six or seven 
percent. 



map units, except pegmatites. This observation, 
and the fact they are not strongly foliated, indicates 
a post-metamorphic, Middle Paleozoic age. Fur- 
ther support for a Middle Paleozoic age derives 
from the fact that compositionally the trondhjemites 
resemble many of the large intrusive bodies of the 
Blue Ridge. These bodies, for example, the White- 
side, Stone Mountain, and Mount Airy plutons, are 
of established Silurian or Devonian age. The 
compositional similarity suggests a close genetic 
and therefore temporal relationship. 

Trondhjemite is intrusive and exhibits sharp, 
commonly discordant contacts with all the highly 
foliated metamorphic rock units on these quad- 
rangles. 



Pegmatite 

FIELD OCCURRENCE AND DESCRIPTION 

Pegmatite occurs throughout the Canton 
Quadrangle and much of the Sandymush Quad- 
rangle. Pegmatites that intrude the Ashe Metamor- 
phic Suite contain coarse muscovite. Those intrud- 
ing the Earlies Gap Biotite Gneiss, Sandymush 
Felsic Gneiss, and other Middle Proterozoic rocks 
are generally muscovite-poor and biotite-rich. 
Pegmatite is commonly crosscutting and lenticular 
to tabular in shape. Thickness varies from a centi- 
meter to a few tens of meters. Although very thin 
pegmatites are locally abundant, it was practical 
only to record the larger pegmatites on plates 1 and 
2. Because the pegmatites weather and decay so 
thoroughly, their orientation is often difficult to de- 
termine. 



PETROGRAPHY 



AGE AND CONTACT RELATIONSHIP 

An absolute age for the trondhjemite is not 
available. Although attempted, radiometric dating 
has not been satisfactorily accomplished. 
Trondhjemite is intrusive into all of the bedrock 



Thin sections were not made of pegmatite. 
Because of the coarse-grained nature of a pegma- 
tite, a hand-sample description is adequate. Peg- 
matite is white to mottled white and pink in color. 
Its texture is coarse grained to very coarse grained. 
It contains plagioclase, K-feldspar, quartz, biotite, 



33 



and/or muscovite. Other accessory minerals may 
occur in pegmatite. 

AGE AND CONTACT RELATIONSHIP 

Muscovite-bearing pegmatites in the Spruce 
Pine Mining District have an age of about 390-435 
million years (Kish, 1983). Although the San- 
dymush and Canton Quadrangles are 50 miles 
southwest of Spruce Pine, the Spruce Pine pegma- 
tite age is accepted for similar pegmatites in this 
area. 



places in each quadrangle. Commonly, the largest 
alluvial deposits occur in the flood plains of the 
major streams. On the Sandymush Quadrangle the 
largest flood plain deposit occurs where Willow 
Creek joins Sandymush Creek. This large alluvial 
deposit provides the largest flat area and the best 
farming land in the quadrangle. A similar area is 
found on the Canton Quadrangle along the Pigeon 
River in the southwestern corner of the map in the 
vicinity of the Plott Farms Addition. These large 
flood plain deposits represent deposition that took 
place during flood stages when the streams were 
out of their banks. 



The pegmatite bodies have sharp, well-de- 
fined contacts with the surrounding country rocks. 
Pegmatite is the youngest bedrock unit on the 
quadrangle as it intrudes and crosscuts all other 
bedrock units on the map. 



Surficial Deposits 

Throughout the Blue Ridge Mountains of 
western North Carolina, thin deposits of loose, 
unconsolidated, relatively recent surface debris 
cover extensive areas. These surficial deposits are 
divisible into two classes based chiefly on their 
mode of transport — alluvium and colluvium. 
Alluvium is formed by running water depositing 
clastic material in stream channels and flood plains. 
Colluvium is the coarse- to fine-grained material 
mantling hillsides and slopes that has been moved 
downward mainly by gravity. Although not shown 
on the accompanying bedrock maps, alluvial and 
colluvial deposits occur throughout the two quad- 
rangles. These surficial deposits, along with soils 
and vegetation, mask the bedrock geology of the 
quadrangle. A detailed map of the surficial depos- 
its is beyond the scope of this project. 



ALLUVIUM 

Alluvium or alluvial deposits occur in stream 
valleys, both in their flood plains and channels. 
Significant accumulations exist at only one or two 



Alluvial deposits of the Sandymush-Canton 
Quadrangles consist of boulders, cobbles, pebbles, 
sand, silt, and clay-sized particles. Deposits within 
the stream channels contain all of these different 
sized sediments, but they are poorly sorted and not 
very extensive. Beyond the banks of a stream, 
flood plain deposits may build up as a result of 
flooding. These deposits consist of poorly to well- 
sorted, stratified gravel, sand, silt, and clay. The 
deposits are rarely greater than 15 feet thick. 



COLLUVIUM 

Colluvium or colluvial deposits mantle much 
of the sloping land throughout both quadrangles. 
The material is a product of weathering (mass 
wasting), sloping land, and gravity. In steep ter- 
rain, colluvial accumulations include abundant 
coarser-sized material, no matter what the bedrock 
material. In gently sloping terrain it requires a 
more massive bedrock to produce a more bouldery 
colluvium. Colluvial materials range in size from 
clay particles to giant boulders larger than houses. 
Quite commonly, where several huge colluvial 
boulders are touching, they form cave-like open- 
ings. In some areas these openings are intercon- 
nected and create lengthy passageways. 

Colluvial deposits are classified according 
to their characteristic shapes. In fact, when they are 
large and well formed, their distinctive form is 
easily recognized on topographic maps. The collu- 



34 



vial deposits observed on the Sandymush and 
Canton Quadrangles include talus, block fields, 
and colluvial tongues, sheets, or aprons. All of 
these colluvial forms are commonly modified and 
dissected by running water. 

Compositionally, colluvial materials reflect 
the bedrock units from which they develop. The 
more resistant rock types produce the more abun- 
dant particles. The more massive rock units pro- 
duce the larger colluvial particles. 



AGE 

Alluvium and colluvium are deposits of 
clastic material released by local erosion of the 
surrounding mountains. Erosion of the Blue Ridge 
has been going on since at least Mesozoic time, 
over a quarter of a billion years ago, but it is almost 
inconceivable that remnants of detritus this archaic 
are still present in the area. Those materials must 
have long since been transported far out of the area. 
Most investigators infer the bulk of the relatively 
ephemeral surficial deposits formed much more 
recently during glacial intervals of the Pleistocene 
Epoch (e.g. King, 1964; Mills et al, 1987). Al- 
though glaciers certainly were not present in the 
local area, the climate was likely quite severe, 
thereby promoting the formation of extensive detri- 
tal accumulations. It is also clear that these depos- 
its are currently being created and reworked, nota- 
bly during occasional, high-energy storms. Thus, 
the deposits have been generated intermittently 
through time with the frequency related to major 
climatic conditions. The alluvial and colluvial 
deposits are therefore classed as Quaternary in age. 



GEOLOGIC STRUCTURE 

f 

At virtually every outcrop in the area one 
may readily observe features of rock deformation. 
Planar surfaces and relic layers, that is, lithologic 
contacts and beds as well as foliation surfaces, are 
tilted, warped, or folded. Structural discontinui- 
ties, or faults of the layers are common, and mylo- 



nite zones, from microscopic to map scale, are 
widespread. In addition, fractures and cracks, or 
joints, are ubiquitous. Based on analysis of these 
deformation structures and supplemental mineral 
and rock radiometric ages, a historical deforma- 
tional sequence may be constructed (table 11). 
Many similar studies have been done throughout 
the Appalachians with the cumulative, integrated 
evidence showing that a series of rock-deforming 
and metamorphic episodes spanning a billion years 
or more have occurred. 

In the southern Appalachian Blue Ridge it is 
widely accepted that three principal episodes of 
deformation andmetamorphism, or orogenies, have 
affected the region. They are the Middle Proterozoic 
Grenville orogeny, about 1.2 to 1.0 billion years 
ago, the Early to Middle Paleozoic Taconic oro- 
geny, approximately 470 to 430 million years ago, 
and the Late Paleozoic Alleghenian orogeny about 
300 to 280 million years ago. Each of these lengthy 
and complex episodes affected the then extant 
rocks in its own peculiar manner. In addition, 
events of lesser intensity have also left their mark 
on the rocks in the region. 



Proterozoic Structures 

The oldest, or Grenville event, affected rocks 
throughout eastern North America. It has been 
studied most extensively in eastern Canada and the 
Adirondack area of New York State where these 
highly deformed and metamorphosed rocks are 
widely exposed. In the southern Appalachians, 
Grenville-age rocks form the core of the Blue 
Ridge and crop out intermittently as far south as 
Georgia. However, subsequent Paleozoic-age 
deformation and metamorphism profoundly over- 
printed and largely obliterated features produced 
by Grenville events. 

In the local area, strata existing about a 
billion years ago are now represented by five 
formations. Three of these consist mostly of lay- 
ered rocks; the other two are more massive units. 



35 



Table 1 1 . Geological development of the Sandymush and 
Canton area 

Quaternary. Erosion and formation of surficial deposits; 
continued regional uplift and joint development. 

Tertiary and Mesozoic. Subaerial erosion; variably ac- 
tive epeirogenic uplift. 

Permian - Pennsylvanian. Alleghenian deformation. 
Major northwestward movement of the Blue Ridge allochthon on 
deep, subhorizontal faults, local low-grade metamorphism, and for- 
mation of mylonite zones. 

Early Devonian - Silurian. Intrusion of pegmatite bodies 
and trondhjemite dikes and sills. 

Early Paleozoic. Widespread orogenic deformation and 
metamorphism correlated with the Taconic orogeny. Development 
of the pre-metamorphic Holland Mountain thrust fault, major and 
minor folds, and pervasive foliation. Foliation or schistosity devel- 
oped in the Ashe and Snowbird formations; existing foliation and 
layering of the older rocks was transposed and locally enhanced. 

Metamorphic conditions attained sillimanite and kyanite 
levels. In the older rocks, most of which had undergone Grenville, 
high-grade Proterozoic-age metamorphism, some retrogression 
occurred. This retrogression is expressed mainly in the mafic units 
(i.e., hornblende to biotite; olivine and pyroxene to serpentine and 
anthophyllite). 



Latest Proterozoic. Deposition of Snowbird Group sedi- 



ments. 



Late Proterozoic. Intrusion of ultramafic rocks, deposi- 
tion of Ashe Metamorphic Suite sediments and volcanic materials. 

Middle or Late Proterozoic. Mylonitization occurred. It 
is especially pronounced or well preserved in the Doggett Gap 
Protomylonitic Granitoid Gneiss. Steatization of protoliths of the 
talc bodies in north part of area also took place. 

Middle Proterozoic. High-grade metamorphism and 
deformation associated with the Grenville orogeny. The Doggett 
Gap, Spring Creek, Sandymush, Earlies Gap, and Richard Russell 
Formations were metamorphosed, at least into the upper amphi- 
bolite facies. Undoubtedly, this major orogenic event involved 
wholesale recrystallization and metamorphic differentiation to pro- 
duce banded and foliated gneissic rocks. Granitic material intruded 
and crystallized to form protoliths of the very coarse-grained Doggett 
Gap unit and the coarse-grained Spring Creek Granitoid Gneiss. 
Mafic material also intruded to form protoliths of the talc bodies and 
the more massive mafic and ultramafic rocks. 

Middle (?) Proterozoic. Formation of the protoliths of the 
Sandymush Felsic Gneiss, Earlies Gap, and the Richard Russell 
Formations. These were likely layered felsic and mafic volcanic 
materials with only minor sedimentary components. 



The layered units are the Sandymush Felsic 
Gneiss, Earlies Gap Biotite Gneiss, and the Rich- 
ard Russell Formation. Their layering, although 
certainly long since transposed into foliation sur- 
faces, likely reflects original compositional vari- 
ations. 

The massive units, the Spring Creek Grani- 
toid Gneiss and the Doggett Gap Protomylonitic 
Granitoid Gneiss, originally were granitic plutonic 
bodies. They may have been medium- or very 
coarse-grained phases of one pluton, or they may 
represent two separate magmatic bodies. We inter- 
pret these to have intruded the presumably older, 
layered units. However, contacts are now so over- 
printed by subsequent tectonic events that it is 
virtually impossible to determine the original rela- 
tionships at field exposures. Both plutonic units 
contain an internal tectonic and metamorphic fab- 
ric. The Spring Creek Granitoid body is gneissic 
with some mylonitic elements. The Doggett Gap 
has a ubiquitous protomylonitic fabric that locally 
grades to mylonitic or gneissic texture. 

In the northwest corner of the Sandymush 
Quadrangle the outcrop pattern and internal fabric 
of the Doggett Gap Protomylonite define a large 
fold (see plate 1). The axis of this structure trends 
northeast- southwest. However, the Spring Creek 
Granitoid Gneiss comprises both the outer flanks 
and inner core of the fold. This unusual condition 
requires that the rocks were folded twice. First, the 
Doggett Gap and surrounding strata, including the 
Spring Creek, were tightly and perhaps even isocli- 
nally folded. Second, the sequence was later re- 
folded into a relatively open structure to produce 
the present pattern (see plate 1 and section A- A'). 
The northeast-southwest trend of the second or 
later fold parallels regional structural trends and 
regional foliation directions. We therefore infer 
that the second fold developed at the same time as 
did the dominant regional structure. There is little 
argument that overriding regional structural trends 
resulted from Taconic deformation and are of Pa- 
leozoic age. For convenient reference, the two fold 
events are designated F (earlier) and F 2 (later). As 
the mylonitic fabric is likewise folded by the Paleo- 



36 



zoic F , the mylonitic fabric must also be an older 
feature. We infer that the mylonitization and Fj 
folding record complex Proterozoic, Grenvillian 



orogenic deformation. 



It is tempting to consider that the tight, 
nearly isoclinal folding of the Doggett Gap and 
development of its protomylonitic fabric were 
contemporaneous. However, no additional or 
conclusive evidence pertaining to their genetic 
relationship was discovered. Elsewhere in the 
Grenville-age rocks other mylonitic areas were 
observed and mapped. As these mylonites re- 
semble those in the Doggett Gap, we infer that they 
too are Proterozoic in age. 

Throughout the area contacts between the 
several Middle Proterozoic units are commonly 
curved and inflected, indicating at least one epi- 
sode of folding. (See plates 1 and 2.) Because the 
regional Early Paleozoic Taconic foliation vari- 
ably and non-systematically trends across these 
contacts, it is concluded that the foliations postdate 
at least some of the folding recorded by the curved, 
inflected contacts. This folding is therefore also 
correlated with the Grenville-age, F 1 folding previ- 
ously discussed. 



Early Paleozoic Structures 

In contrast to the just-described relations 
between foliation trends and Middle Proterozoic 
rock-unit contacts, foliation trends and lithologic 
contacts of the younger Snowbird and Ashe For- 
mations obviously have systematic, geometrical 
relationships. (See plates 1 and 2; figure 14.) For 
example, near the west edge of the Sandymush 
Quadrangle, Snowbird Group rocks occupy a broad 
southwest plunging syncline. Measurements of 
schistosity in the Snowbird reveal an axial planar 
trend and in cross section the schistosity defines a 
divergent cleavage fan. (See section B-B', plate 1.) 
Divergent fans, on both theoretical and observa- 
tional grounds, are understood to develop during 
folding of a relatively incompetent layer between 
competent layers (cf. Ramsey and Huber, 1983, p. 



181). With regard to the adjacent quartzo-feldspa- 
thic gneisses, the dominantly schistose Snowbird 
which hosts the divergent fan is clearly incompe- 
tent. The conclusion is that folding of the Snow- 
bird and development of its northeast-striking 
schistosity occurred during the same deformation. 

Within the Ashe Metamorphic Suite, geo- 
metrical relations between foliation orientations 
and map-scale folds are also suggestive of axial 
plane foliation. This relation is most clearly shown 
at several places on the Canton Quadrangle (see 
plate 2). The locations are west of Beaverdam 
Creek valley in the vicinity of Rocky Knob and 
Rough Creek, in the area approximately three- 
fourths of a mile west of Newfound Gap, and at the 
south end of Holland Mountain along the schist- 
gneiss contact of the Ashe Suite. At these places, 
foliation in the Ashe is generally parallel to mapped 
trends and limbs. 

The folding just described probably formed 
during the Paleozoic Taconic orogeny. Almost all 
modern studies of geologic structures in the south- 
ern Blue Ridge conclude that this was a complex 
deformational event. There was an early isoclinal 
folding phase with attendant development of meta- 
morphic foliation and transposition of existing 
planar elements, such as bedding, or igneous 
contacts into the plane of foliation. Transposition 
is considered to have been extreme enough to have 
obliterated nearly all the closures, or noses, of the 
early isoclines. Observations in the Sandymush- 
Canton area are quite consistent with this interpre- 
tation. At both outcrop and thin-section scales, 
foliation and compositional layering are essen- 
tially parallel and fold closures attributable to early 
folding are rare to virtually absent. 

However, non-isoclinal, open to tight folds 
of foliation and the parallel compositional layering 
are abundant. They are well defined at map scale 
and are readily observable at many outcrops 
throughout the area. These folds of foliation must 
have formed subsequent to the foliation itself. This 
sequence, development of a principal metamor- 
phic foliation that is parallel to compositional lay- 



37 




Figure 14. Map showing foliation trends, San- 
dymush and Canton Quadrangles. Heavy 
lines are formation boundaries; saw 
teeth are on upper plate of Holland Moun- 
tain thrust fault. Late Proterozoic Ashe 
Metamorphic Suite and Snowbird Group 
are shaded. 

The Snowbird Group, central left on 
the Sandymush Quadrangle, is cutby axial 
planar schistosity which is co-planar with 
foliation that variably crosscuts forma- 
tion contacts between Middle Proterozoic 
units. At some places, the Holland Moun- 
tain thrust truncates foliations in both 
upper and lower plates. However, as the 
fault does not displace the kyanite-silli- 
manite isograd (see plate 2 and figure 19), 
the fault must be syn- to late metamorphic 
in age. 



38 



ers followed by folding of the foliation itself, is 
characteristic of many orogenic belts throughout 
the world (e.g. Turner, 1968). 

An important feature in the region is the 
contact underlying the Ashe Metamorphic Suite. 
The nature of this boundary is open to question as 
the known pertinent evidence is not definitive. 
First, there is certainly a great hiatus between the 
Late Proterozoic Ashe Suite and the underlying 
Middle Proterozoic Earlies Gap Biotite Gneiss. 
Either a fault or an unconformity could cause this 
relationship; however, at no place on the Canton, 
Sandymush, or nearby quadrangles have clasts of 
older units been observed in the overlying Ashe 
Suite. The absence of such clasts argues against an 
unconformity. Second, detailed mapping of the 
nearby quadrangles (Merschat, 1977; Merschat, in 
preparation; Wiener, unpublished mapping) shows 
that different rock units abut the contact from both 
above and below. This relation is suggestive of 
truncation by faulting. Finally, current regional 
interpretations for the Blue Ridge place major 
thrust faults between distinctly different groups of 
lithic units (cf. Mies et al., 1987; Nelson, 1985; 
Higgins et al., 1984). A fault below the Ashe is in 
agreement with this regional model. Based on this 
evidence the contact is interpreted as a fault and is 
here named the Holland Mountain thrust fault. 
Holland Mountain is a long, prominent ridge on the 
east side of the Canton Quadrangle that is underlain 
by the fault. 

Examination of the geologic map shows that 
the Holland Mountain fault has the appearance of 
a folded, low-angle thrust. It has an irregular trace 
and several klippen are present. This folding has 
also affected foliation in the Ashe Suite. Foliation 
trend lines mimic the folding shown by the Hol- 
lan4 Mountain thrust (figure 14), thereby demon- 
strating that the thrust existed prior to folding. Ad- 
ditionally, the metamorphic foliation and trans- 
positional fabric appear to be truncated by the fault. 
This evidence suggests the fault to be post-folia- 
tion in age. Significantly, the fault predates the 
region's metamorphic thermal peak as the closely 
located kyanite-sillimanite isograd obliquely 



crosses the Holland Mountain thrust without de- 
tectable offset (see plate 2). Thus, based on several 
lines of evidence, the Holland Mountain thrust 
fault is a pre- to syn-metamorphic structure. A 
number of other faults in the southern Blue Ridge 
exhibit similar relations; two of the better known 
ones are the Greenbrier fault (Hadley and Gold- 
smith, 1963) and the Hayesville fault (Hatcher et 
al., 1979). 

To summarize, the following sequence 
occurred during the Taconic episode. Regional 
foliation developed and transposition took place 
followed by faulting and open to tight folding. 
Finally, a thermal peak, represented by develop- 
ment of porphyroblastic minerals such as stauro- 
lite, kyanite, and sillimanite, overprinted the de- 
formed rocks. 



Later Paleozoic Deformation 

In the Sandymush-Canton area Taconic 
structures are cut by mylonite zones, small 
trondhjemite dikes, and pegmatite intrusions. 
However, no crosscutting relations between these 
features were discovered and thus relative ages 
with respect to each other are not conclusively 
established. 

Locally, the pegmatites are thin tabular 
bodies that are commonly discordant with regard 
to foliation and compositional layering of the en- 
closing rocks. Butler (1972) points out that region- 
ally the muscovite-bearing pegmatites tend to 
appear in the kyanite and sillimanite metamorphic 
zones. He also notes that contact metamorphic 
effects are absent from around the boundaries of 
the pegmatites. Observations on the relatively few 
pegmatites in the Sandymush-Canton area are in 
agreement with Butler's. There is, therefore, con- 
currence with his conclusion that the pegmatites 
intruded during the waning phases of a metamor- 
phic event. The age of Blue Ridge pegmatites is 
cited as 390-435 million years, or Silurian-Early 
Devonian (North Carolina Geological Survey, 
1985). 



39 



The few small exposures of trondhjemite 
found in the Sandy mush-Can ton area have the 
form of thin, crosscutting, unfoliated dikes. A 
regional study by Yurkovich and Butkovich (1982) 
reports on the orientation of some six dozen 
trondhjemite dikes and sills. They found the intru- 
sives are mostly parallel to the northeast trend of 
the Blue Ridge with a lesser number perpendicular 
to this trend. Paucity of well-exposed dikes in the 
Sandymush- Canton areaprecludes the present study 
from adding to their data. Anderson's widely 
accepted explanation of dike formation (Ander- 
son, 195 1) states that dikes are intruded into zones 
perpendicular to the direction of minimum com- 
pressive stress. Thus, Yurkovich and Butkovich's 
(1982) regional information suggests that the 
minimum compressive stress was oriented north- 
west-southeast at the time of trondhjemite intru- 
sion. This, however, was the orientation of maxi- 
mum compressive stress during Taconic deforma- 
tion. Perhaps the low-stress zones which con- 
trolled the trondhjemite intrusions resulted from 
relaxation of the northwest-directed compressive 
stress field in post-Taconic time. 

In addition to the old Proterozoic myloniti- 
zation previously discussed, the effects of a more 
recent mylonitization are locally present (see fig- 
ure 15). As is quite clear from field relations in the 
central part of the Canton Quadrangle around the 
Williams Mountain-Big Butt area, Taconic-age 
folds and the Holland Mountain fault are truncated 
by a major mylonite unit (see plate 2). Half a mile 
northwest of this area in the region of Wilson Cove, 
Williams Cove, and Turkey Creek Gap, this same 
mylonitization is developed mostly in aluminous, 
muscovite-bearing rocks of the Ashe Metamorphic 
Suite. In this region a small dunite body is anomal- 
ously present in the midst of the Ashe-derived 
mylonite. In the central Blue Ridge dunite nor- 
mally occurs only in rocks much older than the 
Ashe. Its anomalous presence in the Ashe-derived 
mylonite suggests that the dunite has been em- 
placed by the same kinematic processes respon- 
sible for the formation of the mylonite itself. These 
processes must therefore have involved consider- 
able dip slip in the planes of mylonitization. 




Figure 15. Mylonitization. Above, Mylonite of the Ashe 
Metamorphic Suite. Later Paleozoic fluxion structure 
obliterates most earlier features. Coarse muscovite 
porphyroblasts are common. Coin is 1.5 centimeters 
across. Outcrop is along tributary stream to West Cove, 
3200 feet northwest of Big Butt Mountain, Canton 
Quadrangle. Below, Photomicrograph of mylonite of 
the Earlies Gap Biotite Gneiss. A few porphyroclasts 
of plagioclase (PI), biotite (Bt), and quartz (Qtz) re- 
main in a fine-grained ground mass. Crossed polariz- 
ers, sample 513. 



40 



Other areas of mylonite and protomylonite 
are also present. They are most notable in schistose 
rocks of the Ashe Metamorphic Suite, both within 
the body of the unit and at many places along its 
boundary with gneisses of the Earlies Gap Biotite 
Gneiss. It is tempting to infer a genetic association 
between these mylonites and development of the 
Holland Mountain thrust fault. However, as previ- 
ously described, the fault itself is truncated by a 
mylonite zone in the Williams Mountain-Big Butt 
area, thereby demonstrating that the two deforma- 
tional features are not necessarily related in a 
genetic sense. Thus, the mylonitization event must 
postdate the Taconic deformation and metamor- 
phism as do the trondhjemite and pegmatite dikes. 

About seven miles north of the Sandy mush 
Quadrangle is the Hot Springs window. Exposed 
in this structure are unmetamorphosed Paleozoic 
sedimentary rocks surrounded by major thrust faults 
(Oriel, 1950). These faults are part of a regional 
thrust system that evidently underlies the entire 
Blue Ridge to make it a huge allochthonous mass. 
Seismic reflection data (Harris et al. , 198 1 ; Cook et 
al., 1983; Hatcher et al., 1987) suggest that the 
thrust is nearly horizontal beneath the Blue Ridge. 
The most recent work (Hatcher et al., 1987) con- 
cludes that the fault is from two to five kilometers 
below the surface in the eastern Blue Ridge. 
Geologic relations to the west in the Valley and 
Ridge Province establish the age of this faulting. It 
is associated with the Alleghenian orogeny and is 
of Late Paleozoic age. Although not exposed at the 
surface in the local area, the undoubted presence at 
depth of this major thrust, or thrust system, adds 
another dimension to the region's geologic struc- 
ture. In fact, the Late Paleozoic mylonitic zones 
and possibly other features may be related to 
emplacement of the Blue Ridge allochthon during 
the Alleghenian deformational event. 



Mesozoic and Cenozoic Structures 

The Mesozoic and Cenozoic tectonic his- 
tory of the southern Appalachians is mainly one of 
variably active epeirogenic uplift. Associated with 



this is concomitant subaerial erosion. Other than 
joints, specific Mesozoic- or Cenozoic-age struc- 
tures are not known, or at least not identified in 
North Carolina's Blue Ridge. 

The most recent structures in the Sandymush- 
Canton area are fractures or joints that are present 
in virtually every outcrop. These fractures may be 
grouped or classified in several different ways. 
More or less curved joints that tend to parallel the 
topographic surface are locally present. Many of 
these come under the category of sheet, or exfolia- 
tion joints. They are well displayed at the rounded 
bare rock knobs and hillsides underlain by the 
massive Doggett Gap Protomylonitic Granitoid 
Gneiss or the Spring Creek Granitic Gneiss. 

At many places joints coincide with folia- 
tion surfaces. These breaks in the integrity of the 
rock mass are analogous to features called bedding 
joints in sedimentary rocks. 

Other joints are present which are not obvi- 
ously sheet joints or foliation-surface joints and 
have diverse orientations. Several hundred of 
these joints were measured and recorded. These 
data were entered into a standard computer pro- 
gram and recovered as contoured equal-area stere- 
ographic plots. The plots are presented in figure 
16. Figure 17 presents a graphic summary of the 
data in terms of small, quarter-quadrangle do- 
mains, individual quadrangles, and by the full, 
two-quadrangle area. 

Apparently, the smaller the area, the less the 
diversity of joint orientations and the higher the 
degree of concentration in each joint orientation 
maximum. Conversely, plots for data composited 
over the larger one- or two-quadrangle area show 
an increasing scatter of orientations and a lowering 
of the degree of concentration in each orientation 
maximum. Perhaps this tendency is a reflection of 
the overall geologic non-homogenous nature of the 
area. 

The joint maxima diagrams reveal a general 
northwest-southeast trend for the majority of the 



41 




A 




C 






B 



D 



65 





35 




H 






398 



Figure 16. Contoured stereoplots of joint orientations, Sand) 
mush and Canton Quadrangles. Lower hcmisphei 
projection of poles to joints, equal area net. 

A-H - Data plotted by quadrants. 

/ and J - Data for each full quadrangle. 

K - Composite of all joints, both quadrangles. 



42 









74 




V 1 




^ 


A 




B 






77 




81 6 <y 


C 




D 






72 \^A 9 








2RS 




78 7 i 


E 




F 






>057 




V 6 


G 




H 








Figure 17. Orientation of joint maxima shown by strike and 
dip symbols, Sandymush and Canton Quadrangles. 
A-H - Maxima plotted by quadrants. 
I-J - Composite for each full quadrangle. 
K - Composite of all data, both quadrangles. 



43 



measured joints with a subsidiary, nearly east-west 
trend. These principal trend directions undoubt- 
edly have some underlying regional tectonic expla- 
nation. However, considerably more study will be 
necessary to explain this aspect. 

As the present investigation was necessarily 
limited to surface exposures, no first-hand infor- 
mation was obtained on the subsurface extent of 
any jointing. Daniel (1987) made a regional statis- 
tical study of more than 6,200 water wells drilled in 
the Piedmont and Blue Ridge of North Carolina. 
His data show that significant amounts of exploit- 
able water are available 1 ,200 feet or more below 
the surface at some places. This information cer- 
tainly indicates that joints are present and act as 
water conduits at considerable depth in the Pied- 
mont and Blue Ridge. Similar deep joints may also 
be present in the Sandymush-Canton area. 



METAMORPHISM 

Deciphering completely the long, complex 
metamorphic history of the rocks of the Sandymush 
and Canton Quadrangles is well beyond the scope 
of this study. The synthesis presented here incor- 
porates our own observations with data and con- 
clusions of others from work elsewhere in the Blue 
Ridge. 

The areal distribution of metamorphic index 
minerals is important in elucidating the region's 
metamorphic history. Primary control in the two- 
quadrangle area is mainly based on 149 stream- 
sediment samples (figure 18; Appendix 2). Hand- 
sample examination during field traverses and 
subsequent thin-section study of selected samples 
provided important additional data. 



Proterozoic Metamorphism 

In the southern Appalachian Blue Ridge 
several recent radiometric analyses of rock and 
mineral samples have yielded unexpectedly old 
ages. Sinha and Bartholomew (1984) report a 



1 870-million-year age for zircon grains from the 
Lovingston massif in central Virginia. Monrad and 
Gulley (1983), using whole-rock rubidium/stron- 
tium methods, determined a 1 8 1 5-million-year age 
for rocks on Roan Mountain, North Carolina, about 
fifty miles northeast of the Sandymush-Canton 
area. These archaic, Early Proterozoic dates are by 
far the oldest reported in the entire region and their 
significance is not yet clear. They may indicate a 
time of magmatic activity or they may reflect a 
period of extreme metamorphic reconstitution of 
crustal material. One may assume that rocks and 
minerals dating back to this time are precursors or 
sources for subsequent lithic units. 

Documentation of high-grade Middle 
Proterozoic metamorphism is more extensive. For 
example, as long ago as 1916, Watson and Cline 
(1916) described granulite-grade mineral assem- 
blages in Virginia. Bartholomew and Lewis (1984) 
discuss high-grade rocks in the Virginia and North 
Carolina Blue Ridge. McConnell and Costello 
(1982, 1984) describe similarly metamorphosed 
rocks near the western edge of the Blue Ridge in 
Georgia. Radiometric ages of about 1,000 million 
years are recorded from many of these rocks (Ful- 
lagar and Odum, 1973; Rankin et al., 1983). This 
combination of data from so extensive a geo- 
graphic area is firm evidence for concluding that 
regional, high-grade metamorphism occurred dur- 
ing Middle Proterozoic time in the Blue Ridge. 
High-grade metamorphism of this general age in 
eastern North America is commonly named Gren- 
villian. When coeval deformational and magmatic 
effects are included, use of the term Grenville 
orogeny is appropriate. 

On the Mars Hill Quadrangle, located about 
fifteen miles northeast of the Sandymush-Canton 
area, Merschat( 1977) shows the presence of granu- 
lite-facies mineral assemblages. He provides de- 
tailed mapping and descriptions of hypersthene- 
plagioclase rock, hypersthene-biotite-hornblende 
gneiss, and hypersthene granitic gneiss. Kuch- 
enbuch (1979) also examined rocks in the Mars 
Hill area and supported and extended Merschat's 
observations. 



44 



01 



c c 




cr 


T3 








Heavy mi 
dislributio 
percent 




aj 


C 






a> 


0) 
O) 


O- 
O 

o 


0) 
-O 

c 
o 


o 

"O 

a. 


C 


o 


^ 


CO 


X 


LU 


C5 


W 



a 
w 



Snowbird Group 



Ashe Metamorphic 
Suite - Gneiss Unit 




III. 



75 -J 30 J 

0.50 -\ 20 —1 | 

025 zLl' 0= Li_L 



Ashe Metamorphic 
Suite - Schist Unit 



0.75 — 


30 


0.50 — 


20 


0.25 — 


10 
1 



A 



i i . ■ 



Doggett Gap 
Protomylonitic 
Granitoid Gneiss 



0.75 — 


30 


0.50 — 


20 


0.25 — 


.1. 



J_L 



Spring Creek 
Granitoid Gneiss 



Sandymush 
Felsic Gneiss 



0.75 
0.50 
0.25 



0.75 
0.50 
0.25 




u 



■ III 



Earlies Gap 
Biolrte Gneiss 



Richard Russell 
Formation 




0.75 — 


30 


0.50 — 


20 


0.25 — 


10 




■ 



u 



1 

00 












1 i 


1 


1 


1 




- _ - 1 



Note: Open symbol indicates less than 2 percent abundance; refer to Appendix 2 lor exact values. 



Figure 18. Graphs showing average abundance of heavy minerals in stream-sediment samples for individual formations. 

45 



Reconnaissance mapping indicates these 
units correlate along strike with parts of the Earlies 
Gap and Sandymush Formations. Fullagar et al. 
(1979) report a Middle Proterozoic age of 1214 
million years (data recalculated by Rankin, 1983) 
for some Mars Hill rocks based on rubidium/stron- 
tium whole-rock analysis. The Middle Proterozoic 
age determined by Fullagar et al. (1979) in con- 
j unction with Merschat ' s ( 1 977 ) and Kuchenbuch ' s 
(1979) field and petrographic information is evi- 
dence for intense, granulite-grade, Middle 
Proterozoic metamorphism near the Sandymush- 
Canton area. Additionally, our own reconnais- 
sance mapping a few miles west of the Sandymush 
Quadrangle in the Fines Creek area revealed hyper- 
sthene-bearing mafic rocks similar to the granulite 
rocks of the Mars Hill area. 

However, the Middle Proterozoic rocks of 
the intervening Sandymush and Canton Quad- 
rangles, based on their mineral components, record 
metamorphism that does not exceed amphibolite 
facies. In addition, the presence of local, but wide- 
spread, migmatization places the rocks in at least 
upper amphibolite facies. As seen today, the rocks 
are amphibolites, biotite gneisses, biotite granitic 
gneisses, tonalite gneisses, calc- silicate rocks, and 
granitic gneisses. Hypersthene was not identified 
in the field nor was it found in thin section. Also, 
it is not present in any of the stream sediment 
samples. Thus, an apparent anomaly in the meta- 
morphic pattern exists; a lower-grade area lies 
between two higher-grade areas. 



and destroyed once-present diagnostic high-grade 
minerals. As discussed elsewhere in this report, 
evidence for retrogression exists at many places. 
For example, in the field some amphibolites are 
locally converted to biotite schist and gneiss, and in 
thin sections biotite replaces hornblende (see fig- 
ures 6,7). However, it is very doubtful that all 
traces of high-grade minerals would have been 
obliterated throughout the two-quadrangle area by 
retrogression. 

3) The Sandymush-Canton area never at- 
tained so high a metamorphic grade. With more 
detailed geologic mapping and petrologic studies it 
may become apparent that this lower-grade region 
is not anomalous, but actually fits well with an 
overall regional pattern. 

Early Paleozoic Metamorphism 

In contrast to the many uncertainties of 
Proterozoic Grenville metamorphism, Paleozoic 
metamorphism is well documented and has been 
widely studied at many places in the Blue Ridge. 
The major metamorphic interval was between 470 
and 430 million years ago (Butler, 1973). This 
event produced the dominant foliation now seen in 
the rocks as well as a classical Barrovian prograde 
metamorphic sequence. The sequence ranges from 
chlorite or sub-chlorite along the west margin of 
the Blue Ridge into sillimanite grade in the central 
Blue Ridge of western North Carolina (Hadley and 
Nelson, 1971). 



Three possible explanations are: 

1 ) Granulite-grade metamorphic conditions 
existed, but locally the rocks are not of appropriate 
chemical composition to produce granulite index 
minerals. Comparative chemical data are lacking, 
but it is unlikely that the chemical composition of 
similar-appearing rocks in the Sandymush-Canton 
area is very much different from that in the nearby 
high-grade areas. 

2) Granulite-grade metamorphic conditions 
existed, but subsequent metamorphism retrograded 



The kyanite-sillimanite isograd crosses the 
Canton Quadrangle diagonally from southwest to 
northeast with the highest grade rocks lying in the 
southeast part of the map (see plate 2 and figure 
19). The isograd's precise location and configura- 
tion as it crosses the Earlies Gap Biotite Gneiss is 
not known because these rocks do not have the 
proper composition to produce kyanite or silli- 
manite upon metamorphism. Thus, it is necessary 
to project the isograd across the Earlies Gap out- 
crop area. 

In the Canton Quadrangle an area of transi- 



46 




Figure 19. Outline map showing location of the sillimanite- 
kyanite isograd (short-dashed where approximately 
located) and distribution of monazite-bearing rocks, 
patterned area. Location of the monazite isograd, long- 
dashed line, is inferred based on its presence in the Ashe 
Suite and absence from the pelitic Snowbird Group. 
Overstreet (1967) has shown that upon sufficiently 
high regional metamorphism, monazite develops in 
aluminous, metasedimentary rocks. Symbols: 
Zs=Snowbird Group; Zas=Ashe Metamorphic Suite; 
Ydg=Doggett Gap Protomylonitic Granitoid Gneiss; 
Ysc=Spring Creek Granitoid Gneiss; Ys=Sandymush 
Felsic Gneiss; Ye=Earlies Gap Biotite Gneiss; 
Yr=Richard Russell Formation. Saw teeth on upper 
plate of Holland Mountain thrust fault. 



tion exists between kyanite-bearing rocks and sil- 
limanite- bearing rocks. As observed in the field, 
this transition area is characterized by the presence 
of coarse-grained white mica (muscovite), which 
is pseudomorphic after kyanite (see figure 11). The 
coarse-grained mica appears to have developed 
abruptly at the expense of kyanite. Southeastward, 
towards higher grade areas, the porphyroblastic, 
white-mica pseudomorphs gradually disappear and 
sillimanite appears. The width of the transition 
area is variable, but averages several thousand feet. 
The applicable theoretical explanation for this tran- 
sition area is not known to us. It may have resulted 
from one or more of the following: 1) Local falling 
temperatures during unloading (Turner, 1968). 2) 
fluctuations in water pressure connected with 
melting and freezing of a neosome in migmatitic 
areas (Turner, 1968). 3) Increase of oxidation 
ratios causing the amount of biotite and garnet to 
decrease with a complementary increase in musco- 
vite and iron oxides (Chinner, 1966). 

Another mineral whose distribution in pe- 
litic rocks is controlled in part by metamorphic 
grade is monazite (Overstreet, 1967). Monazite 
first appears in the higher-grade portion of the 
kyanite zone downgrade from the kyanite-silli- 
manite isograd. In the Sandymush-Canton area 
only an approximate location for the monazite 
isograd can be drawn. Based on stream sediment 
samples, monazite is present throughout the alumi- 
nous metasedimentary Ashe Metamorphic Suite. 
Several miles northwest the lower grade Snowbird 
Group, which is also composed of pelitic metasedi- 
ments, does not contain monazite. The monazite 
isograd therefore lies between these two units. The 
intervening Middle Proterozoic rocks, however, 
do not have the appropriate composition for mona- 
zite to develop and thus only an approximate loca- 
tion for a monazite isograd can be drawn. Figure 1 9 
shows the distribution of monazite, the broad limits 
of an apparent monazite isograd, and relations to 
the kyanite-sillimanite isograd. 

The northwest part of the Canton Quad- 
rangle and most, if not all, of the Sandymush 
Quadrangle is at kyanite grade. Metamorphic 



47 



intensity in the northwest corner of the Sandymush 
Quadrangle is uncertain as the non-pelitic, granitic 
rocks in that region do not produce diagnostic 
aluminosilicate minerals upon metamorphism. 
However, both kyanite and staurolite are common 
in samples from the meta-pelites of the Snowbird 
Group which extends to within three miles of the 
northwest corner of the quadrangle. 



RETROGRESSION 

The Paleozoic metamorphism was a regional 
prograde event that had different effects on differ- 
ent rocks in the area. For example, the relatively 
aluminous Ashe and Snowbird Group rocks ex- 
hibit minerals and textures indicative of typical, 
Barrovian, upper amphibolite facies metamor- 
phism. 

On the other hand, the much older rocks of 
the Earlies Gap, Sandymush, Spring Creek, and 
Doggett Gap Formations had already been meta- 
morphosed in the Proterozoic with development of 
biotite, hornblende, and various other metamor- 
phic minerals. In these units, the Paleozoic meta- 
morphism acted as a retrograde event. Evidence 
for this retrogression is especially notable in the 
Middle Proterozoic amphibolites. In thin-section, 
biotite replaces previously existing hornblende 
(figures 6,7). In the field some of the thinner am- 
phibolite layers are now altered to biotite schist and 
gneiss. The biotite flakes form a new surface or 
foliation which, though poorly developed, is slightly 
different from the compositional layering. This 
new foliation nearly parallels biotite-rich layers in 
the pre-existing biotite gneisses, biotite schists, 
and granitic gneisses. 

Additional evidence favoring the concept 
of Paleozoic metamorphism having retrogressive 
attributes exists along strike to the northeast in 
rocks of the Mars Hill Quadrangle (Merschat, 
1977; Kuchenbuch, 1 979) and Barnardsville Quad- 
rangle (Merschat, in progress). In these quad- 
rangles, certain mafic bodies have a core of coarse- 
grained, granoblastic, mafic granulite rock. To- 



wards the outer margins these bodies become pro- 
gressively more amphibolitic until at their edges 
they are medium- to fine-grained amphibolites. 
Thus, the cores preserve the old, Proterozoic, granu- 
lite-facies metamorphic suite while the exterior 
portions contain the Palefozoic, amphibolite-facies 
metamorphic suite. The lack of complete amphi- 
bolitization is attributed in part to the dry, water- 
poor character of these rocks. In the Sandymush 
and Canton Quadrangles the contrast in metamor- 
phic grade between the Proterozoic and the Paleo- 
zoic events was probably not as great, but the same 
pattern is present. In this area, unaltered horn- 
blende in amphibolites and pyroxene grains in the 
calc-silicate rocks of the Earlies Gap, Sandymush, 
Spring Creek, and Doggett Gap units are relics 
from the Middle Proterozoic metamorphism. The 
alteration of amphibolite to biotite schist and gneiss 
is the result of the younger, Paleozoic metamor- 
phism. Alteration of the dunite bodies is also 
attributed to this major, Paleozoic metamorphic 
event. In them, primary olivine and pyroxene are 
locally altered to serpentine, talc, anthophyllite, 
and perhaps even chlorite or vermiculite. 



TIMING 

As previously mentioned, Taconic meta- 
morphism took place about 470 to 430 million 
years ago (Butler, 1973). It was a regional dyna- 
mothermal event that was episodic in character. 
During the earliest stage existing planar features, 
such as compositional layering, were transposed 
into the plane of a newly forming regional folia- 
tion. A dynamic event, emplacement of the Hol- 
land Mountain thrust fault, took place after the 
foliation was well developed. Evidence for this is 
especially striking near Big Butt Mountain in the 
central part of the Canton Quadrangle where folia- 
tion trends in the Ashe Suite are abruptly truncated 
(see plate 2). After faulting, or at least after major 
displacement along the fault, the rocks and the 
thrust fault were both folded. 

The final Taconic metamorphic episode was 
a regional thermal peak during which porphyro- 



48 



blastic indicator minerals such as kyanite and silli- 
manite crystallized. This thermal peak occurred 
after faulting had ceased as shown by the lack of 
offset along the kyanite-sillimanite isograd where 
it crosses the Holland Mountain fault (see plate 2). 
It was also during this thermal peak that local 
migmatization occurred over a widespread area in 
the Ashe Metamorphic Suite. 



Late Paleozoic Metamorphism 

A post-Taconic, low grade metamorphic 
event is commonly reported in the Blue Ridge (e.g. 
Butler, 1973). In the study area there also are in- 
dications of a late, low-grade event. Chlorite, a 
mineral commonly associated with greenschist- 
facies metamorphism, is visible in amphibolite 
outcrops in the northwestern part of the Sandymush 
Quadrangle. It also occurs in a few thin sections of 
various gneiss varieties from across the area. Thin 
sections containing chlorite are from the Sandymush 
Felsic Gneiss (4 sections), and Earlies Gap Biotite 
Gneiss (3 sections). This metamorphic event may 
be considered a low-grade, greenschist-facies, retro- 
gressive metamorphism. The time of occurrence is 
poorly constrained by evidence in the local area; 
however, we infer the event may have occurred 
during the late Paleozoic Alleghenian orogeny. 



MINERAL RESOURCES 

Nowhere on the Sandymush or Canton 
Quadrangles has there ever been a major mining 
operation. Mining and prospecting occurred on a 
relatively small scale, but currently all mining 
properties are inactive and abandoned. An inven- 
tory of the area's mines, pits, prospects, and occur- 
rences is presented in Appendix 3. 

Past production data are minimal; however, 
mica was probably of greatest commercial value, 
followed by feldspar, sand and gravel, and crushed 
stone. Local residents reported that kaolin was 
mined from one locality near Wilson Cove in the 
Canton Quadrangle. Soapstone for local use was 



excavated from shallow pits in the northern part of 
the Sandymush Quadrangle. Also, a locality in the 
central part of the Canton Quadrangle once pros- 
pected for industrial corundum, is now open to 
mineral collectors on a fee basis. 

Several dunite bodies, most notably the ones 
near Newfound Gap and Harmony Grove Church 
on the Canton Quadrangle, were prospected for 
olivine and associated corundum, vermiculite, and 
chromite. 

Scheelite, an important ore of tungsten, 
unexpectedly was discovered to be a component in 
many stream sediment samples (seeAppendix 2). 
The scheelite-bearing samples all come from 
streams draining the Earlies Gap and Sandymush 
formations. Previously, scheelite had been found 
by Mr. James Stewart, a local prospector, in only 
one small area in the southeast part of the San- 
dymush Quadrangle (Stewart, 1986, oral commu- 
nication). Hand samples provided by Stewart con- 
tain scheelite grains and aggregates up to 3 milli- 
meters across. The host rock is medium-grained 
amphibolite to calc-silicate rock. The samples 
exhibit metamorphic alteration, or retrogression, 
as coarse biotite flakes are abundant on some 
foliation surfaces. 

Monazite was not previously recorded from 
this area. However, it is widely present in stream 
sediment samples from the south and east part of 
the area (Appendix 2). It is most abundant in 
samples draining the schist portion of the Ashe 
Metamorphic Suite (figure 19). 



ACKNOWLEDGEMENTS 

We are indebted to the many residents and 
landowners in the area for their continued interest 
and strong support of our work. Almost without 
exception, we were graciously offered unrestricted 
access to their properties. In a number of instances 
specific outcrops or geologic features that we might 
otherwise have overlooked were brought to our 
attention. 



49 



The several community clubs and organiza- 
tions of Sandymush, Beaverdam Valley, and 
Crabtree strongly endorsed our efforts and we wish 
especially to thank all the members and officers of 
these organizations. 

During the summer of 1987, Clay Haldeman 
and Terry Kicinski, geology students at Western 
Carolina University, collected, panned, and did 
preliminary mineralogic work on heavy mineral 
stream sediment samples. Results from this work 
add an important body of factual data that signifi- 
cantly helps our geologic understanding and inter- 
pretation of the area. The authors also wish to add 
a personal appreciation of Terry. His life was 
senselessly taken before this report was completed. 
He was a good person who worked hard and played 
well. He vigorously enjoyed life's activities and 
brightened the lives of his acquaintances. We miss 
him as a person; our science, and humanity, is the 
poorer for his absence. 

Arthur Nelson examined some of the area's 
outcrops during a field excursion in the spring of 
1987. Later, he guided us through parts of the 
Greenville Quadrangle especially to show and 
discuss rocks of the Helen Group and Richard 
Russell Formation. After field work was com- 
pleted, he and Ken Gillon reviewed drafts of the 
Sandymush and Canton geologic maps and subse- 
quently examined the manuscript for this report. 
Both offered many acute comments which have 
helped us improve the maps and the text. We are 
grateful for their thoughtful assistance and thor- 
ough reviews. 

Sigrid Ballew has been of inestimable help 
in preparing and proofreading the manuscript. In 
addition to typing sequential drafts of the text, she 
prepared the tabular data summaries, including 
many of the calculations, and did all with care, 
precision, and dispatch. 

David Spain, Manager of the Asheville 
Regional Office of the Department of Natural 
Resources and Community Development, provided 
helpful and much appreciated administrative sup- 



port from the very beginning of the project. 

Jeffrey Reid, Chief Geologist of the North 
Carolina Geological Survey, gave us continual 
encouragement and assistance with both geologic 
and production aspects of the maps and report. 



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52 



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53 



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55 



APPENDICES 



APPENDIX 1. HEAVY MINERAL PROCEDURE. 



In Field 

1. Collect a standard-size stream- sediment 
sample from the gravelly portion of stream bed. 
Nominal weight, 13.6 kilograms. 

2. Pan sample on site using standard 16-inch 
gold pan. Discard very coarse material. Resulting 
pan concentrates mostly weighed between 50 and 
300 grams. 

In Processing Laboratory 



a. Using short-wave and long-wave 
ultraviolet illumination, scan heavy mineral con- 
centrate, noting especially scheelite and zircon. 

b. Using a scintillometer, scan heavy 
mineral concentrate. Only samples especially rich 
in monazite had readings of even twice back- 
ground. 

6. Using an alnico hand magnet, remove all 
magnetic material. Weigh and record the mag- 
netic portion as magnetite. 



3. Screen pan concentrate at 0.6 mm (No. 30 7. Petrographic Examination: 
sieve). Store oversize. 

a. Successively split non-magnetic 

4. Perform heavy liquid separation using tetra- portion to a convenient size and mount grains on a 
bromoethane, specific gravity 2.96. Bag and save microscope slide using standard 1.67 index of re- 
light fraction, fraction oil. Store remainder. 



In Mineralogic Laboratory 



b. Scan entire slide to note all mineral 
species present. 
5. Fluorescent and radioactive mineral exami- 
nation: c. Systematically traverse slide count- 
ing and identifying about 200 grains. 



8. Perform calculations and tabulate data (see 
Appendix 2). 



APPENDIX 2. HEAVY MINERAL ANALYSES OF PANNED CONCENTRATES, 
CANTON AND SANDYMUSH QUADRANGLES. 

Notes: 

1. Sample locations are shown on plates 1 and 2 by red circles with appropriate sample numbers. 

2. Formation symbols: Zs=Snowbird Group; Zag=Ashe Metamorphic Suite, Gneiss unit; Zas=Ashe Mctamorphic Suite, Schist unit; 
Ydg=Doggctt Gap Protomylonitic Granitoid Gneiss; Ysc=Spring Creek Granitoid Gncisss; Ys=Sandymush Felsic Gneiss; 
Ye=Earlies Gap Biotite Gneiss; Yr= Richard Russell Formation. Use of multiple formation symbols indicates drainage area sampled 
includes more man one formation. Parenthesis indicates formation comprises a very minor portion of drainage area. 

3.'Trace' indicates mineral observed in sample, but not not encountered during grain-counting procccdure. 

4. Black opaque grains are mostly ilmcnite. 

5. Mineral abbreviations: MAG.=magnetite; HBLD.=homblende; STAUR.=staurolite; KYAN.=kyanitc; SILL.=sillimanite; 
TOUR.=tourmaline; SCH.=scheelite; UNIDENT.=unidenlified. 

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61 



APPENDIX 3. SUMMARY OF MINES, PITS, PROSPECTS, AND OCCURRENCES. 



Name; 

Quadrangle, Map Number 
Location by North 
Carolina Coordinates 



Dimensions 



Remarks 



Mica 



C. B. Wells Spar mine; 
Sandymush, 1 
720,450N; 886,250E 



Lum Sprouse (Reeves) 
mine; Sandymush, 2 
729.150N; 867.450E 



200-foot-long cut, 
20-30 feet deep. 



Several shallow 
pits and cuts, less 
than 5 feet deep. 



This was primarily a feldspar mine with 
production coming from a zoned pegmatite. 
Scrap mica was also recovered; principal 
activity was in the 1950's (Lesure, 1968). 

Lesure (1968) noted this pegmatite pro- 
duced feldspar and scrap mica, mainly in 
1928 and 1942. The mica is stated to 
be bent, locky, cracked, and with biotite 
intergrowths. 



Big Cove mine; 
Canton, 1 
683.700N; 883,250E 



A series of cuts, 
pits, adits, drifts, 
and stopes are pre- 
sent in an area about 
600 feet long and 
200 feet wide. 



The weathered, zoned pegmatite was worked 
from 1915-23, intermittently from 1932-43, 
and in 1952. Production was greenish- 
brown sheet mica, perhaps as much as 500 
pounds (Lesure, 1968). A mine map (Olson 
and Parker, 1943) shows the pegmatite 
trends N45E and has a vertical to very 
steep southeast dip. The pegmatite is at 
least 300 feet long and up to 30 feet 
thick. 



Mica mine, name 
unknown; 
Canton, 2 
664,000N; 882,750E 



H. A. Hipps prospect; 
Canton, 3 
697,950N; 876.250E 

L. L. West prospect; 
Canton, 4 
685.050N; 879.450E 

Frank Medford prospect; 
Canton, location un- 
certain, not shown 
on plate 2; Coordi- 
nates approximated 
from Lesure (1968): 
697,000N; 855,000E 



A series of trenches 
and shallow pits. The 
two largest excavations 
are 50 to 75 feet long 
and 25 to 30 feet wide. 

40-foot-long cut, up 
to 12 feet deep. 



10-foot-long prospect 
pit. 



No records are known for this mine 
and present local residents know little 
of its history. Small bent books of 
mica are on the dumps suggesting that 
the primary output was scrap mica. 

A small amount of cracked, stained, or 
bent mica was recovered with most, if not 
all activity in 1943 (Lesure, 1968). 

During 1938-1940, a small amount 
of ruby-colored sheet mica was produced 
(Lesure, 1968). 

A small amount of rum-colored, "A" struc- 
ture, stained sheet mica was taken from a 
4-foot-thick pegmatite (Lesure, 1968). 
This prospect was not found during the 
present study. 



62 



APPENDIX 3 (continued). SUMMARY OF MINES, PITS, PROSPECTS, AND OCCURRENCES. 
Mica (continued) 



Champion Fibre Co. 
prospect; Canton, 
location uncertain, 
not shown on plate 2; 
Coordinates approxi- 
mated from Lesure (1968): 
673,500N; 853,500E 



35-foot-deep shaft, 
short drifts. 



A small amount of light ruby, "A" struc- 
ture, bent, reeved, ruled, and clay- 
stained sheet mica was recovered from a 
weathered, quartz -cored pegmatite with 
most activity probably taking place during 
World War II (Lesure, 1968). Recent con- 
struction and development around the town 
of Canton has encroached on this area and 
the prospect was not relocated during the 
present study. 



Olivine 



Newfound Gap deposit; 
Canton, 5 
685,950N; 878.850E 



Crops out in an oval 
area about 700 feet 
long by 300 feet wide. 



This dunite body has been known and 
prospected intermittently since the 19th 
century. Hunter (1941) conservatively 
estimates more than 6 1/2 million tons 
of serpentinized dunite and about 1 1/3 
million tons of relatively unserpentinized 
granular olivine are present above local 
stream level. 



Hominy Grove deposit; 
Canton, 6 
680,550N; 868,500E 



Olivine occurrence; 
Canton, 7 
686,600N; 878,250E 



Olivine occurrence; 
Canton, 8 
683.300N; 859.500E 



Olivine occurrence; 
Canton, 9 
682.250N; 857,100E 



Outcrops and float 
indicative of dunite 
are present in an 
area several hundred 
feet across. 



Several outcrops of 
dunite are present here. 



A 25-foot-wide 
exposure. 



Hunter (1941) evidently considered this 
outcrop area near Harmony Grove Church 
to connect with dunite at locality 10, 
about 2,000 feet to the west. With this 
interpretation he estimated more than 
20 million tons of serpentinized dunite 
and one million tons of granular olivine 
to be present; however, it is not likely 
that the deposit is nearly so large. 

Geophysical work by Hirt et al. (1987) 
indicates that two masses of dunite are in 
this locale. The largest was determined 
to be about 350 feet long, 230 feet wide, 
and to extend no deeper than 350 feet. 

Scattered pieces of altered ultramafic 
material, dominantly talc-anthophyllite 
rock, are present in a red, clayey soil, 
and indicate the presence of an unexposed 
dunite body. 

The outcrop is composed of altered ultra- 
mafic rock that contains talc, serpentine, 
anthophyllite, chlorite, and vermiculite. 



63 



APPENDIX 3 (continued). 

Olivine (continued) 

Olivine occurrence; 
Canton, 10 
680.500N; 866,350E 



SUMMARY OF MINES, PITS, PROSPECTS, AND OCCURRENCES. 



A 10-foot-wide 
exposure. 



A small roadside outcrop of serpentinized 
dunite occurs here. Hunter (1941) appar- 
ently considered this outcrop to be part 
of the Hominy Grove olivine deposit. 



Olivine occurrence; 
Canton, 11 
678,500N; 849,600E 



A small outcrop of altered ultramafic 
rock was exposed during construction of 
Interstate 40 during the late 1960's 
(J. Philip McElrath, personal commu- 
nication). A few pieces of float are now 
scattered about the area. 



Feldspar 

Feldspar mine, name 
unknown; Canton, 12 
691.100N; 849,350E 



Feldspar prospect, 
name unknown; 
Canton, 13 
703,050N; 862,200E 

C. B. Wells Spar mine; 
Sandy mush, 1 
720.450N; 886.250E 



One large pit and 
several small trenches. 
The pit is about 75 
feet long, 40 feet wide, 
and with walls 25 to 30 
feet high. 

The prospect excava- 
tion here has a 12- 
foot-high face. 



The dumps contain abundant clean 
quartz, weathered feldspar, and minor 
biotite. 



A 25-foot-thick pegmatite contains 
feldspar and quartz with minor biotite 
and traces of muscovite. 



See previous discussion of this mine. 



Sand and Gravel 

Sand and gravel pit, 
name unknown; Canton, 9 
660.750N; 850.200E 

Sand and gravel pits, 
Sandymush, locations 
uncertain, not shown 
on plate 1. Coordi- 
nates are very approxi- 
mate: 

Caldwell pit: 731.000N 

869,000E 

Canto pit: 733,500N 

877,500E 



Sand and gravel have been recovered 
from deposits in the flood plain of the 
Pigeon River in this vicinity. 

Notes on a small-scale map in the files 
of the N.C. Geological Survey indicate 
that sand and gravel have been produced 
from flood plain material along Little 
Sandymush Creek at two localities prior 
to 1969. There is little remaining sign 
of mining activity in the area now. The 
material was likely used in local road 
construction. 



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APPENDIX 3 (continued). SUMMARY OF MINES, PITS, PROSPECTS, AND OCCURRENCES. 



Crushed Stone 



Crushed stone quarry, 
name unknown; 
Sandymush, 9 
723.550N; 881.100E 

Crushed stone quarry, 
name unknown; 
Sandymush, 10 
732,300N; 863,950E 



Stone from this small roadside quarry, 
developed in biotite gneiss of the Earlies 
Gap Biotite Gneiss, was likely used for fill 
and subgrade in local road construction. 

Stone from this small roadside quarry, 
developed in amphibolite of the Sandymush 
Felsic Gneiss, was likely used for fill 
and subgrade in local road construction. 



Corundum 



Presley mine; 
Canton, 15 
684,750N; 866,300E 



Corundum (?) prospect; 
Canton, 16 
697.200N; 879,500E 



Two or three shafts 
are reported. Presently 
an exposed face in a hill- 
side excavation is about 
150 feet long and 25 feet 
high. 



30-foot-long trench 
with an adit. 



Blue to bluish-gray corundum occurs in 
pegmatite dikes that crosscut biotite 
gneiss interlayered with amphibolite. 
Pratt and Lewis (1905) state that the 
corundum occurs in rough crystals and 
fragments, some of which weighed 6 to 10 
pounds. This is a popular location for 
mineral collectors who are charged a fee 
for entry. 

The property owner had been told that 
these diggings were for corundum. Rocks 
in the area are largely amphibolite; the 
adit and small dump contain massive actin- 
olitic rock. No corundum was observed 
during this study. 



Kaolin 



Kaolin prospect, name 
unknown; 
Canton, 17 
692.750N; 862,350E 



Local residents report that kaolin was 
prospected or mined on a small scale in 
this locality before World War II. 
Subsequent road construction has oblit- 
erated all signs of mining; however, 
kaolinized pegmatite is exposed in the 
present road cuts at this site. 



Talc 



Talc prospect; 
Sandymush, 3 
743.750N; 886.900E 



Shallow hillside ex- 
cavation, 25 feet 
long, 15 feet wide, 
10-foot-high face. 



Talcose rock, or soapstone, dips 56 
degrees NE; an 8-foot width is exposed in 
the face. The landowner reports this 
material was cut into blocks, primarily 
for local use in hearths and chimneys. 



65 



APPENDIX 3 (continued). 

Talc (continued) 

Talc prospect; 
Sandy mush, 4 
750,100N; 853,800E 



SUMMARY OF MINES, PITS, PROSPECTS, AND OCCURRENCES. 



Shallow sidehill cut, 
40 feet long. Face at 
end of cut is 8 feet 
high. 



A 10-foot thickness of talcose rock, or 
soapstone, is exposed. This locality has 
been prospected intermittently for many 
years, as recently as the early 1980's 
The material has been used locally 
in fireplace and chimney construction. 



Talc prospect; 
Sandymush, 5 
740.850N; 855,850E 



Talc occurrence; 
Sandymush, 6 
742.250N; 885.900E 



Several small, shallow 
collapsed pits are 
present on the crest 
and southeast side 
of a small spur. One 
of the pits contains 
an outcrop of soapstone 
about 2 feet wide and 
3 feet high. 

Outcrops and float 
are scattered about 
an area several hundred 
feet across. 



Soapstone from this shallow pit has 
apparently been used in local fireplace 
construction. 



Talcose and chloritic rocks are present 
at this site. 



Talc occurrence; 
Sandymush, 7 
738.750N; 862,800E 



Talc occurrence; 
Sandymush, 8 
729,550N; 863.450E 



Keith (1904) maps two small soapstone 
bodies in this vicinity. A search of the 
area revealed only a few outcrops and 
float of soapstone. 

Keith (1904) maps a soapstone body here; 
however, a search of the area revealed 
only a small outcrop and float of talcose 
and chloritic rock. 



66